This looks like a good starting point https://en.wikipedia.org/wiki/Interbreeding_between_archaic_and_modern_humans https://en.wikipedia.org/wiki/Interbreeding_

This looks like a good starting point https://en.wikipedia.org/wiki/Interbreeding_between_archaic_and_modern_humans https://en.wikipedia.org/wiki/Interbreeding_between_archaic_... And https://en.wikipedia.org/wiki/Human_evolution#Neanderthal_and_Denisovan https://en.wikipedia.org/wiki/Human_evolution#Neanderthal_an... Neanderthals are thought to have split from Sapiens between 180K and 800K years ago. It looks like the science is not settled on whether Denisovan separated from the common ancestors of Neanderthal and Sapiens or whether Denisovan are closer to Neanderthal.