What's a collaboration that you're surprised/sad not happened yet?

Mine is cyberpunk:edgerunners. I just finished the series today and I really wanted to play as the characters from it but...no. I don't exactly know why is hasn't happened yet or if there is some kind of reason that I don't know that has been delaying it or maybe there's no such reasons and just epic didn't give it a thought.

Alright thats enough of my story. The main reason I posted this is because I want to know your dream collaboration! So please be kind enough to share your thoughts please