Some kind of zombie....
The way we are going, a future species will be digging up our bones making up stories about us.
I really doubt humans will be alive then. If they are they will no longer be human, they would be a descendant and their appearance has not been laid out yet as it depends on who breeds with who from now until then.
I think humans will become cyborgs merging their bodies with technology.
If it's a triathalon... everyone will be really tired
Planet of the Apes !
Going from what caveman looked like and moving forward past what we are today as a visual.... I would think something like the green aliens people talk about seeing
Like the rat race but with taller, louder rats. ;-)
likely all dead if we dont stop our foolish warring with each other