If life exists on Mars, it won't be found close enough to the surface to be easily discovered, a team of European scientists has concluded.
With the solar system warming, more ice is thawing on the red planet, so I believe we may be able to find bacterial or microbial life thriving, having come out of hibernation, so to speak. As the planet warms, I do not think they will have to go deep to find life at all. Just let the ice thaw.