This is a relatively new finding, within the last several months it seems. But basically analysis of western sub saharans show "ghost" dna from an unidentified group of archaic hominids. It was present on all the subjects tested, but I believe this was only done on west subsaharans. Assuming it's in all subsaharans it would show we couldn't have come out of africa since it's not present in eurasians or amerindian populations. I'd provide a link but I'd need to google one for you which you can do easily. Robert sephr has a joutube channel and has covered this in several videos as well as a bunch of other shit you might be interested in so I'd start there. His hypothesis is basically that cro-magnon interbred with several different groups of archaics in different regions creating what we today call races. Obvs we whites bred with neanderthals, asians bred with neanderthals and denisovians and africans who bred with neither of those groups bred with this other group, he believes it was homoerectus.