Most of our history people didn’t live long enough to get cancer. Also few white people lived in hot climates.
the worst sunburns I have ever gotten were during snow skiing. The sun reflects off the snow.
My point is that if one stays outside year round ... one builds up a natural tan gradually and naturally that protects you. Now common sense must be used and one must avoid the sun during the hottest parts of the day, just as one would naturally were there no air conditioning.