Mikasa and Zeke. He might be afraid of her. She might resent him for what he's making Eren do.
I also think it's possible that they might reach a mutual understanding because they both seem to genuinely care about Eren. They both played are playing a protective role for him, just in very different ways. I also wonder how Mikasa would feel about him given that she was raised taken in by Grisha.
Probably won't happen, but there are some interesting possibilities there I think.