The universe hold countless stars and billions of galaxies. Our galaxy holds about 100 to 400 billion stars and the possibilities are endless. But essentially, the whole galaxy and universe wasn't made out of countless galaxies and stars just for a tiny blue planet to have life, alien life must exist but just haven't found it yet when we haven't done anything to figure out how to make faster than light travel across star systems. While we don't have much definite evidence, it's more than likely.
But it's only in out imaginations to wonder what's alien life is but as primitive as we are, we could likely never find out the mysteries of an uncaring spacetime continuum. But our concepts for alien life is astrobiology in hopes of thinking how they might appear according to our understanding. For the record of how big the universe is
Since the expansion of the big bang 13.8 billion years ago, the universe has been continuously expanding due to dark energy and the observable universe is all that we can see, the light hasn't had anytime to reach us and likely never will. Despite this, it's obviously plausible for more galaxies or cosmic filaments to exist beyond this to contain much more extraterrestrial life, medium possibilities for more higher advanced civilizations than us.
But if our universe is infinite, we could never observe anything beyond of what we can currently see but still holds the possibilities of things yet to be imagined.
But yes definitely, we haven't found yet :)
