Bottom line is the black contribution in every war before Korea was negligible. Maybe not due to blacks themselves.
The US military was segregated until Korea. There was one Black Division in Europe in WW2. It acquitted itself well. IIRC. It had white officers. The Army was only willing to go so far.
Also in WW2 Blacks in the Navy did serve on ships, but as Ships Servicemen: running the galleys, laundry, etc.
We can thank the evil Woodrow Wilson for the segregation that he reinstituted in Federal Service when he was President. He started the socialist policies that Frankie the Limper later built on.