OK, some qualifiers. Mostly, Mars is very cold and icy, even areas in local summer, even at the equator. At the poles in winter, carbon dioxide sometimes freezes out. Ouch.
And this liquid water is very salty, which makes it freeze at lower temps. And it’s mostly under the surface of the hillsides, just sort of trickling down hundreds of feet. Still, liquid water!
Liquid water is one of the prerequisites usually listed for life on a planet. All our planet’s biology needs it, and we’re basically reasoning from a sample of one planet. But here’s another planet in the same solar system that meets (just barely) that requirement for life. And not in some distant past before Mars cooled off and before its lack of a magnetic shield let the solar wind blow away some of its atmosphere and liquids. Now.
It’s time to fiddle with the Drake equation just a smidge. The Drake equation lays out the chances of finding another civilization in the galaxy by considering the chances of each factor. How many stars are there in the galaxy, and how many of those stars have planets, and how many of those planets have the conditions (like liquid water) that could support life. The chances of a planet being able to support life are arguably just a bit higher than previously thought.
Don’t listen to anyone selling you oceanfront property on the Red Planet, but that’s a lot to think about!