Sicily was a major focus of the First and Second Punic Wars. The first Punic war ended with Carthage handing over major grain-growing areas on the island, and the port of Lilybaem to Rome as spoils of war.
The second Punic War started as an uprising by Hannibal, a descendant of one of Carthage's native born generals, in Spain against "creeping" Roman domination. With little Carthagian support (but the implicit approval of the government), he raised a "mixed" army, crossed the Alps, and invaded Italy. Because Rome's defenses were too strong for him, he ended in the southern part of the peninsula, fighting a seesaw war.
During the Second Punic War, Carthage sent some 77,000 men to try to recapture Sicily, more than Hannibal had at any one time. They might have done better to reinforce Hannibal with them instead.
But maybe the Carthaginians could have done even better by directing Hannibal to Sicily to receive these reinforcements, re-capture Lilybaem and the grain lands, and prevent Syracuse from falling into Roman hands. Or did naval, or other considerations, rule this out?