We don’t know of any yet. But the probability seems to be high. There are just so many stars with planets around them. There are probably at least as many planets in our galaxy as stars, so around 100 billion.
For me, that just seems to be too many for there not to be life on one of them.
It would be weirder if there wasn’t life on other planets. A key part of astronomy and cosmology is the assumption that our patch of space and the universe we can observe isn’t special. With the huge number of star systems and planets it is very likely that life could exist somewhere because it exists here. Whether or not we’ll ever find it is a completely different matter!