Slavery wasn't really a thing in pre historic Hunter gatherer society:
"Somewhat more convincing are statistical surveys of large numbers of societies that show that slavery is rare among hunter-gatherers, is sometimes present in incipient agricultural societies, and then becomes common among societies with more advanced agriculture. Up to this point slavery seems to increase with increasing social and economic complexity."
Which makes sense, the benefit of slavery is that the master can expropriate all the surplus a person can generate, but hunter gatherers don't really generate surplus. Combine this with the difficulty of keeping someone against there will without a state and people specialized in violence to keep them in line and slavery isn't really that viable.
In general hunter gatherer tribes were anarchic as consensus and social cohesion were necessary both to make sure you don't starve and to be able to fight off other tribes