A human is presently a Homo Sapien, no more, and no less. At least from a biological perspective.
From a philosophical perspective, the lines get more blurred. But let's think a little about the concept itself. We keep using the word "human", as if it was a synonym to a sentient and intelligent being. Were the neanderthals human, despite not being homo Sapiens? yes. They were our cousins, and therefore were just as advanced as our ancestors were at the time. But let me ask you a different question: What about a species with the same intelligence and sentience as us, but was, say, evolved from reptiles or fish? Is that species "human"? No, it is a sentient species with the same amount of intelligence as us. Therefore it is not "human"; and yet they are the same. Is a bipedal humanoid robot a human? no. But, my point is: Despite not being human, it still has characteristics that are typically attributed to humans.
And as someone pointed out, we have never actually had the chance to apply this discussion elsewhere than fiction. At this point, it is merely theories.
But if I had to try to answer this question, it would be: If you are classified beneath the "Hominidae" family, and you have sentience, and the intelligence to question yourself and the things around you, then you are a human.