I would really appreciate it if someone could tell me anything about this military uniform. Thanks so much for any help!
It seems to be Polish.
This drawing I found shows a uniform that has more accessories, and this may lead to confusion. I assume your photo pictures a young private with low or no grades.
Another picture of a Polish soldier clearly shows similar numbers on the collar: https://ar.pinterest.com/pin/510173464030294530/?nic=1
This is the Uniform of the Polish "Blue Army" which was a contingent which belonged to the French army and therefore received its name due to receiving French model 1915 uniforms. This unit consisted of men from all around the world of Polish ethnicity and this unit formed in 1917 fought on the Western front in World War one and would later be involved in the Polish-Soviet war. This unit by the end of ww1 would number 68,500 men. Here are some some photos of the soldiers and uniforms.