At the very least the ice age allowed for the peopling of the Americas by trapping a ton of water into glaciers. With all of the water frozen up into glaciers, the Bering Strait became a strip of land ~1000 miles wide that led from Siberia to Alaska. Beringia (as the land bridge is called) was then accessible for Pleistocene animals and humans to walk across. When the ice age ended, and most of the glaciers melted, the Americas were cut-off from Siberia. Following the end of the ice age, people in the Americas began to occupy land that was previously glaciated. They also probably had some minor changes in subsistence as the megafauna (e.g. mammoths) died off due to climate change.

That's the bare minimum. If you're interested in knowing more about it, let me know!

[edit: slightly more info]