Do You Believe in Extraterrestrial Aliens?

I think this is quite unlikely, because it requires several rare factors to occur at the same time, being:

1) Extraterrestrial life forms being near Earth
2) Extraterrestrial life forms being nearly as intellectually resourceful and developed as humans

If this were the case, it would probably be very difficult to hide this information from mankind, especially considering how many adversary governments there are.

Also, there is a video on the YouTube channel Kurzgesagt that explains why we're doomed if there were extraterrestrial life forms near us.