Something I learned a while back was darker skin tones are more common in hotter climates, while lighter skin is found in colder climates. In other words, if they’re closer to the equator, natives are more likely to be dark skinned. While folks native to places closer to the north/south poles are lighter skinned.
It has something to do with the way skin processes sunlight. Darker skin absorbs sunlight better and gives more protection against sunburn. Lighter skin can’t absorb sunlight as well and is more delicate, in a sense, so it is more susceptible to sunburn. Hence why folks in colder climates are lighter skinned.
Now, this is just something I saw while researching one time. I’m no expert, so yeah. But, hopefully this helps, even if it just inspires you.