360,000 died and 280,000 were wounded for the Union Army. Pretty big price to pay fighting for freedom.
For the record Europeans took Africans for about 450 years starting in 1441. The Arabs were in this business several hundred years before the Europeans (starting in circa 750 AD). In the US, we often start the discussion in 1619 but by then there were already millions of enslaved Africans in Cuba, Haiti, Brazil and elsewhere in the Americas.