Colours represent the first human arrival in a given area.
The question of “When did people first arrive in Africa?” is effectively meaningless. Humans evolved in Africa and as such a date cannot be given. There is a sizable amount of evidence to suggest the evolution of homo sapiens occurred across the entire continent, and not solely in East Africa as was previously thought. Homo sapiens remains dated to upwards of 200,000 years ago and have been found in North, South and East Africa. Whatever the case may be, it seems humans permeated all of Africa by 100,000 years ago at the very least.