We've already shared some comments from XCOM 2’s creative director Jake Solomon on Mario + Rabbids: Kingdom Battle. He loved what he saw and thinks it's fantastic that the collab is happening. Now we also know that Solomon wishes he got in on the idea first!
“If I had know we could have done that, I would have pitched that to Nintendo a long time ago.”
Nintendo has a close relationship with Ubisoft, so I don't know that they would have moved on the idea without them. I mean, Miyamoto does love those Rabbids!