The San people of southern Africa are claimed to be the living human group with the most ancient divergence from the rest of humanity, around 200,000 years ago. That they are so similar to the rest of humanity has always made me wonder if the commonly accepted divergence date ranges should be pushed back.
From the Wiki:
"A DNA study of fully sequenced genomes, published in September 2016, showed that the ancestors of today's San hunter-gatherers began to diverge from other human populations in Africa about 200,000 years ago and were fully isolated by 100,000 years ago, well before the first archaeological evidence of modern behaviour in humans."