- Space missions have determined that conditions on Mars were hospitable for life for at least some periods during its history, but there has never been direct proof of life existing there. - Any kind of life on Mars would be [microbial](https://www.amnh.org/learn-teach/curriculum-collections/cosmic-horizons-book/fossil-microbes-mars) in nature. It's possible that microbial life exists there today under the planet's ice caps or in subsurface lakes. - [NASA's Perseverance rover](https://mars.nasa.gov/mars2020/) and its helicopter companion, [Ingenuity](https://www.space.com/ingenuity-mars-helicopter-perseverance-rover), are currently looking for signs of ancient life on Mars - scouting out life immortalized in microscopic fossils, for instance. - Interestingly, humans could have [contaminated Mars](https://www.bbc.com/future/article/20210510-could-the-perseverance-rover-have-carried-life-to-mars) with our own microbes that hitched a ride from Earth. It's likely any microbes that travelled like this would be vastly different to the forms in which they left our home planet, however. The pressures of the travel would have caused them to evolve. Further reading: https://blogs.scientificamerican.com/observations/im-convinced-we-found-evidence-of-life-on-mars-in-the-1970s/ https://www.bbc.com/future/article/20210510-could-the-perseverance-rover-have-carried-life-to-mars