A species is defined by one simple thing: if individuals can interbreed and produce fertile offspring. There are complications related to ring species and few others, but they're not applicable here.
All human beings from all over the world can interbreed and their children will be fertile themselves (with the same rate of accidental infertility they would find in their own populations). As such, it would be completely preposterous to claim that there is more than one species of human on the planet today.
wolves are considered different species from dogs but they can produce offspring
The definitional limit on interbreeding includes geography and preference; black/brown/polar bears can and do interbreed in captivity but because they live in different locations and they look sufficiently different/have different diets we consider them different species.
If Aliens landed on our earth 20k years ago and used our definition of the word there's no doubt in my mind they'd consider us different species, we'd be like bears. As far as I can tell the only reason we don't classify people as different species is for the sake of society, as people would naturally then try to determine differences and rank them, which has an obviously bad long-term outcome.