Given all the answers above we certainly can find more cases, but I'll give a current emerging example:
The China - U.S. cold war (for Africa)
At the 12th US-Africa Business Summit held in Maputo, Mozambique there were 11 African heads of state and government and around 1,000 business leaders.
During the event, US officials unveiled that a $60 billion investment agency which seeks to invest in low and middle-income countries, with a very special focus on Africa.
6 months before that, National Security Advisor John Bolton presented to the US administration what he called "The New Africa Strategy".
According to the presentation, "Great power competitors, namely China and Russia, are rapidly expanding their financial and political influence across Africa. They are deliberately and aggressively targeting their investments in the region to gain a competitive advantage over the United States."
While both are mentioned, the focus in most of the meetings and debates that happened recently is on China.
My many Africa is now the next possible big battleground for the escalating trade war between Beijing and Washington.
Africa at this moment is witnessing the first signs of an emerging new cold war.
The obvious signs of that are the ever-increasing foreign military presence, planned investments and general diplomatic tension.
This is nothing new to Africa and clearly something detrimental to African development and peace.
Economic wars
China's approach to Africa was and is trade-focused oriented. Africa became one of the top destinations for Chinese investment after Beijing introduced the so-called "Go Out" policy (Zǒuchūqū Zhànlüè) in 1999. This policy encouraged private and state-owned business to seek economic opportunities abroad. And they succeeded both in Europe and in Africa, but in the case of Africa the media coverage is a lot lower. The practical result: Chinese trade with Africa has increased 40-fold over the past two decades. In 2017 it reached $140 billion. Between 2003 and 2017, Chinese foreign direct investment (FDI) funds have increased more close to 60-fold to $4 billion / year. FDI stocks stand now in 2019 at $43 billion and those are practical things because a significant part of that has gone to infrastructure and energy projects: expansion of African railways, various infrastructure projects in Angola (among others: hydro-power plant under construction), Djibouti, Ethiopia (Africa's longest railway between these last 2), Kenya and Nigeria.
US, by contrast, has viewed Africa as a battlefield where it can confront its enemies, whether the Soviets, 'terrorists' or now the Chinese; while that they did not focus on developing serious economic relations. As a result, trade between the US and Africa has decreased from $120 billion in 2012 to just over $50 billion today in 2019.
So the US it will not be able to challenge Chinese economic presence on the continent. In 2018 Chinese President Xi Jinping pledged $60 billion more be invested in Africa.
The US has continuously accused China of using "debt to hold states in Africa captive to wishes and demands" while propaganda-warning the African nations of "a significant threat to US national security interests".
Africa started to own China, currently that being around $83 billion.
To make the situation clear, Djibouti's President Ismail Omar Guelleh has stated: "The reality is that no one but the Chinese offers a long-term partnership."
The pressure the US is currently exerting on African countries to move away from partnerships with China could hurt African economies. It could force African countries into making choices that are not in their best economic interests and miss out on important development projects or funding. While something like this should not happen, history tells us that it practically does almost every time.
The current US-China trade war is already affecting Africa, as is everyone else. According to the African Development Bank, it could cause as much as a 2.5 percent decrease in GDP for resource-intensive African economies and a 1.9 percent dip for oil-exporting countries.
Militarization
Both US and China are militarily involved in Africa. The escalating tensions between them could end up threatening the security of the whole continent.
Over the past 15 years, the Chinese People's Liberation Army has been engaged in a number of security missions across the continent, making modest auxiliary troop contributions to peacekeeping operations in the Democratic Republic of Congo, Liberia, Mali and Sudan. It has also contributed millions of $ of peacekeeping equipment to the African Union Mission in Somalia and provided significant funding to the Intergovernmental Authority on Development for its mediation in South Sudan.
In 2017, the first Chinese overseas military base was opened in Djibouti. The facility has the capacity to accommodate 10,000 troops and officially it is supposed to provide support for the ongoing anti-piracy operations of the Chinese navy (maritime routes security). Rumors say that this is only the 1st base in many.
But as said above, China focused on the Economy part, while US focused on the military presence. Over the past few years, US Africa Command has run some 36 different military operations in 13 African countries, including Burkina Faso, Cameroon, Central African Republic, Chad, Democratic Republic of Congo, Kenya, Libya, Mali, Mauritania, Niger, Somalia, South Sudan and Tunisia. It has more than 7,000 troops deployed on the continent. This may not seem much, but the operations done there are quite significant if seen in an over-all manner.
US has a main base in Djibouti and at least 34 other military outposts scattered across the continent. Various military operations including drone attacks and sabotage are launched from all these outposts. The US directly supports the armies of Egypt, Nigeria, Ethiopia, Mali, Niger and others as well as the G5 Sahel force tasked with 'counter-terrorism'.
This type of operations become an increasingly destabilizing factor.
Practically, US counts on the conflicts and social unrest to counter the Chinese influence in Africa.
Regional tensions
Djibouti has recently found itself at the centre of US-Chinese diplomatic war. Being a host to military bases of both superpowers, they are forced o tr to keep things in balance.
In 2018, Djibouti seized control of its Doraleh Container Terminal from the Emirati company DP World, claiming its operation of the facility was threatening its sovereignty. The Djibouti authorities had feared that the UAE's investment in the nearby Port of Berbera in the autonomous Somali region of Somaliland could challenge its position as the main maritime hub for Ethiopia's large economy.
Its decision to terminate the contract with DP World triggered a sharp reaction from Washington, a close Emirati ally. The US administration fears that Djibouti could hand over control of the terminal to China.
"Should this occur, the balance of power in the Horn of Africa - astride major arteries of maritime trade between Europe, the Middle East, and South Asia - would shift in favour of China. And, our US military personnel at Camp Lemonnier could face even further challenges in their efforts to protect the American people", National Security Advisor John Bolton warns.
Djibouti was forced to declare publicly that it would not allow China to take over the terminal.Even so, ever since, the US sought to secure a possible alternative location for its African military base in Eritrea. Saudi Arabia and the UAE were encouraged to pull Eritrea out of its decades-long isolation. In a matter of months, long-time enemies Ethiopia and Eritrea concluded a peace agreement to end their 20-year-old cold conflict and the UN lifted sanctions on Asmara. As a result, Eritrea could emerge as a strategic rival to Djibouti, offering its coast for foreign military and economic facilities. The UAE, for example, has already set up a military base near the port of Assab. If this is not cold war tactic, what is ?
Another area that has been an unofficial battleground is Sudan. China had been a long-term supporter of President Omar al-Bashir. Under his rule, Beijing came to dominate its oil industry, buying some 80 percent of its oil and thus providing Khartoum with much-needed cash to wage war against various rebel groups (part of which had various levels of US-support). After South Sudan gained independence in 2011, China continued to be a close partner of the Sudanese regime, remaining its main trading partner. Sudan in fact became the biggest beneficiary of the African investment package China pledged in 2018, and were spared about $10 billion debt.
When mass protests erupted in December last year, Beijing stood by al-Bashir, who it saw as the main guarantor of stability in the country, which falls on strategic routes, part of its Belt and Road Initiative.
Meanwhile, the US had repeatedly demonstrated that it did not want al-Bashir running for another term. His removal was approved in Washington, which has since appeared to back the interests of Saudi Arabia and the UAE in the country. This is a full on-going operation of which results / effects we will soon see.
This political confrontations have added to the already rising tensions between other players in the region, including Egypt, Gulf countries, Iran and Turkey. The US administration has particularly favored Emirati, Saudi and Egyptian interests which have emboldened these three countries in their efforts to shape regional dynamics to their advantage.
Thus, in the long-term, given the pre-existing faultiness and conflicts in the region, the China-US cold war, if continued, will definitely have a detrimental effect, not only on Africa's economy but also on its security.