In short, yeah, there is a high possibility that aliens exist. There have been many sightings of a UFO but the most widely accepted theory is that of the "Goldilocks Zone".
Now, what are these so-called "Goldilocks Zones"? Well, a Goldilocks zone according to how NASA defines it is the range of distance with the right temperatures for water to remain liquid. So, basically, this zone is neither too hot nor too cold for carbon-based creatures to live and for water or dihydrogen monoxide to exist. This is also the exact reason why inhabiting Mars is an option.
Now, can we find these "Goldilocks Zones" in other star systems? Scientists have said that logically every star system should have a Goldilocks Zone. Even in our very own solar system, we have over 5 planets in the Goldilocks Zone.
A planet being in a Goldilocks Zone need not be habitable, as there are other factors like the availability of water that contribute to the existence of a species.
Well, we shouldn't doubt the existence of alien species because if we did doubt it, it would be like taking a spoonful of water from the ocean and telling that sharks do not exist.
Imagine if aliens from other planets are reading this blog 😂