An "alien race", when speaking about non-Earthly beings, make no sense. They would not be a "race" (of humans), but a different species. Just like a dog is not a "race" of humans, but a separate species. Within dogs, there are different races or "breeds" as they call them in that context. The point is not specifically the word "race" but the mixing-up of two very different concepts.
Two individuals of the same species (such as two humans from different parts of the world) can have offspring even if they are from different races.
Two individuals of different species, such as a human and a dog, cannot have offspring. Because they are different species. Of course, they are also different races, but that is only technically true and doesn't make sense in the context, since the species (which is much more fundamental) is different.
So, an "alien race" (not talking about "illegal aliens" from a different country on Earth) makes no sense. It would be an alien species or, if you want to avoid the words race/species for whatever reason, an "alien life-form".
So why do they keep butchering the English language when they must know better? I see this all the time in sci-fi context.
The English language is being slowly morphed into absolute gibberish, even among people who clearly must know better.