I believe there is other life forms here(both on and around our home planet and our star), just we can't comprehend it.
Think of a small rock, you pick it up, in itself there are so many microscopic life forms and probably more we can't see. Or if you don't understand that example, think of an ant. We squash them, drown them, pick them up, blow them away, they would have no idea wtf we are. Just the same I believe there is something bigger our minds just simply cannot comprehend what that is.
Apart from that, there are other life forms like our own. Haven't you seen Star Wars?

I want to go to Kashyyyk and get a pet dog-bear hybrid. I wonder what a Wookie would look like shaved.
Also, who can say that it's not possible that there could be other human-like species on Mars etc. and have avoided detection via cloaking devices
May the Force be with you,
Scot