It's not that Aliens haven't seen us, but some of the secret organisations are already working with these aliens. Although they want to keep it a secret. There has been many abduction incidents happening constantly throughout the world and the abductees claim of having an encounter with aliens. Who knows what they are planning while lurking behind the secret hidings?
It's all speculation at this point. So many different theories telling totally different things. Not sure what to believe actually.
All we can do is to hope for the bright future for us and our coming generations. Who knows what's there in the middle of deep oceans and vast deserts?