These people are humans.
Given that humans only evolved around then, it's reasonable to ask about tribes that split off.
"modern humans evolved in Africa possibly from Homo heidelbergensis, Homo rhodesiensis or Homo antecessor and migrated out of the continent some 50,000 to 100,000 years ago"
https://en.wikipedia.org/wiki/Human_evolution
I suppose this could be mostly answered with a DNA test, on further thought.
I took this to mean they've been isolated at least in terms of not having genes cross over.