Genetic evidence points to a interbreeding event between the common ancestors of Neanderthals and Denisovians and a newly recognised "super archaic" human group that diverged 2 million years ago. The breeding event seems to have happened 700,000 years ago. Our family tree looking more like a braided vine
https://m.phys.org/news/2020-02-earliest-interbreeding-event-ancient-human.html