I hope it happens, but as of now I seriously doubt it goes ahead.
Tom wants it, and I'm sure the UFC would love to put it together. I can just see Jon holding out for a fee they will never pay.
Jon has already strongly implied he won't fight Tom, that he's going to angle for the Poatan fight and he is happy to just walk away if the UFC won't give him what he wants.
UFC might offer him 7, 8, even 10 million to fight Tom. Jon demanded $30 mil to fight Ngannou and I think he's probably asking for a similar amount now.
"Fuck you money to where it won't sting win or lose" sounds like it's gonna be a lot higher than he's ever been paid to this point.