Life on Mars has always been a subject of much curiosity and happens to also be much debated. Why, there was even a show on this before it got cancelled!
However, scientifically speaking, no proof of past or present life has been found on Mars to date. All that can be attested is that during the ancient Noachian time period, the surface environment of Mars had liquid water which might have been habitable for microorganisms. This, of course, does not prove that Mars has habitable conditions necessarily indicate life.
Yet, speculations still rage on!