Is there life on Mars? Many scientists hope so.
Scientists are anxious to find life elsewhere in the galaxy because they keenly sense the problem that the uniqueness of the earthly biosphere poses for their philosophical embrace of metaphysical naturalism. If life can be shown to have emerged on other planets then it would lend support to the view that as improbable as a naturalistic origin of life may seem it is not so unlikely as to be uncommon or rare.
The problem is that finding simple life-forms on Mars would prove nothing about the origin of those life forms. Many astronomers believe that a meteor impact of sufficient magnitude on the early earth could have blasted trillions of encysted bacterial or algal spores into space. Some of those may well have rained down upon and colonized Mars and even thrived there for a time so that any life we find there may, for all we know, have originated on earth.
In other words, finding single-celled life forms on Mars would solve none of the intractable difficulties faced by naturalistic theories of the origin of life on earth.