By 1945, more than 1.2 million African Americans would be serving in uniform on the Home Front, in Europe, and the Pacific (including thousands of African American women in the Women’s auxiliaries). Most never saw combat. Washington thought they wouldn't or couldn't fight and not smart enough to fly planes and other such skills which changed as the war drug on. Another problem was the service was segregated which meant blacks were assigned based on race and not skills.
As the war continued some black units saw combat however not many. As a result only about 700 were killed in combat. On D-Day, the First Army on Omaha and Utah Beaches included about 1,700 African American troops. This number included a section of the 327th Quartermaster Service Company and the 320th Anti-Aircraft Barrage Balloon Battalion, which protected troops on the beach from aerial attack. Soon the all-black 761st Tank Battalion was fighting its way through France with Patton’s Third Army. They spent 183 days in combat and were credited with capturing 30 major towns in France, Belgium, and Germany.
https://www.nationalww2museum.org/sites/default/files/2017-07/african-americans.pdf