Predator has now gotten to the point where you could make one the straight hero of a movie. The first one was a bad guy all around, but nowadays they have twisted senses of honour, they ally with humans if need be, they clean up their messes, and in Predators one is the brave underdog fighting the super-uber-Predator who captured him.
So what could you do with that? It probably needs some humans, so maybe set it on Earth. Put a Predator between them and something more threatening, and give it a reason to defend them. (Not Alien, it’s been done, and only done well in the comics.)
This could be expanded on further - let’s say there are small numbers of not-that-humanoid aliens operating in secret on earth, pursuing various agendas. Since they don't look like people, give them cloaking devices, and a hard time making alliances with humans - although not impossible, especially if somebody wants to play a human ally. Put government departments on their trails, so they have to act in secret or end up in Area 51. (You can always do an “Escape From Area 51” episode too.) Ramp up the danger later on, so we have to get involved.
A lone “outsider” fighting for humanity is pretty common for superheroes and superhero-y urban fantasy, so why not modern-day SF?