It's about 1.3 times the size of Earth, it's smack in the middle of it's stars habitable zone, and it's only four light years away.
All of which makes Proxima b the best target to study terrestrial planets. Does it have life? We don't know yet...but it might be possible for new propulsion technology to get a probe there to take a peek in only 20 years (we've had probes out that long to reach the outer system).
Meanwhile, large telescopes under construction might be able to directly observe this world and at least establish if it has an atmosphere. It's likely tidally locked, but...we know that isn't a dealkiller for life.
So...let's take a peek.