In the repercussions of the lost battle the United States added two sections to general order 100 issued by the Department of War, the first said that once a man became a soldier he had no own responsibility for actions of war. The other said that there were no difference between colors, if the enemy would enslave or sell the captured soldier, the Union would answer with execution as punishment.
Even President Lincoln had something to say about this. In a statement he did on July 30, 1863, he spoke of the people's individual rights and equality, so if the enemy killed African-American soldiers the Union would answer with executing the soldiers of the enemy. If they sold or enslaved these soldiers the government would answer with putting an enemy soldier in hard labor where he would be working until the captured soldier was released. This statement was indeed useful. The Confederacy no longer went to extremes.
If one consider that more than 200,000 African-Americans served in the Union army during the American Civil War, then it is very likely that every African-American today have a relative that fought in the Civil War. The African-Americans made one eight of the total Union army. One third of the recruited African-American soldiers were killed during the war.