Probably send another probe there with fishing poles to see if any catfish are in the water! Ya never know, man !
What do you think would happen if they found actual water on Mars? Would we attempt to live there? Send people over? Or just continue to research?
Mars has no magnetic field so radiation would burn you to a crisp
Were there, Space 1999 on Moonbase Alpha.
There already is a plan to send people to mars, it was announced 4 years ago - the catch is that it is a one way trip only, no coming back.