Will we find evidence Human-Like species once lived on Mars? Personally, I highly doubt it. I’m not even sure we will find evidence of ANY kind of past life on Mars, even microbial. If we even found evidence of a fossil of an extraterrestrial microbe on Mars, or for that matter on a meteor or anywhere else that originated somewhere other than Earth, it would completely revolutionize science and religion and be a huge culture shock for millions of people.
If we were ever to discover aliens (we haven’t yet), they would most likely not be more advanced than humans. In fact, the majority of aliens we are likely to discover will be microbes. The term (extraterrestrial) “aliens” does not imply a race of advanced beings.
If, however, we were to come across aliens more advanced than microbes, they might be something like this guy below.
The only aliens on Earth are the ones from other countries on Earth.
Other than that, we haven’t even found a fossil of a microbe of an alien from another world and at present have no proof that life exists anywhere else in the universe other than here (though we suspect there is life out there somewhere).