I don't think we will find traces of life on Mars, we would have found them already. Perhaps Earth is the only place where life has emerged. It is so improbable and so incomprehensible to be able to obtain from organic matter a molecule of life. There are all conditions on Earth and yet it hasn't happened again for 4 billion years. And it's even more improbable to go from one molecule of life to billions of molecules to make plants, then animals, and even more improbable to make intelligence. in terms of probabilities it must be enormously large, even infinite in the sense of almost impossible.