What do migration routes of homo sapiens reveal about their survival skills and ability to adapt?

I would say the very same species H. sapiens adapted to various climates and environments.

They didn't evolve anatomically like other animals would have done which takes hundreds of thousands of years. They just adapted their behavior: diet, clothing, fire, cooking, tooling ... as soon as they reached a new environment.

Other animals rely on the slow process of evolution. That means a species split into 2 sub species, then 2 different species, one still adapted to the former environment, the other adapted to the new one e. g. with a thicker fur if the new place is colder (like polar bear vs grizzly during last ice age)