No matter how many landers NASA and JPL send to Mars or anywhere else, they will never find life. Of course, these scientists are thoroughly marinated in evolutionary theory, so they will never allow themselves to honestly consider the implications of the fact that life exists nowhere else but on Earth.
Any alien advanced enough to reach Earth from so far a distance should also be advanced enough to overcome whatever environmental factors they are dealt with.
“Hey Xyt67 - I’m cold!”
“Hold on - the signal is weak, but I’m getting most of it from Earth - a show on how to build igloos!”