IMO It isinevitable that life exists away from Earth.
Most of it may be no more than microbes, but in the vastness of the Galaxy (let alone the Universe), there MUST be a life form (several, probably) that we would recognise as sentient.
Whether it exists NOW, is another matter.
In the scale of the age of the Universe, WE have only been around for a short period, and the chances of another comparable civilisation rising to coincide is small. So even if we discover warp drive, we may never encounter another sentient species.
It's a bit like expecting the Roman Empire to travel east and bump into Ghengis Khan - they were just not around at the same time.