Marvel has an embarrassment of riches now that the Fox/Disney deal is done, and they have the kind of problem every studio wishes they could have. Kevin Feige has to find a way to introduce the X-Men characters into the MCU, and while any decision on that may be years away, one Marvel mutant could arrive way sooner. Of course, that would be Deadpool, who is the most popular Fox character to come over and certainly won't be getting recast. Ryan Reynolds is definitely hear to stay.
All of that said, we still don't know how Deadpool will debut, and a new rumor from MCU Cosmic (judge accordingly) says three options are on the table. Exactly one of these is pretty cool, and all three are unlikely for various reasons.
Let's get the potentially awesome one out of the way first. There's a chance Deadpool could have a prominent guest-starring role in the next Spider-Man sequel starring Tom Holland. Everybody thinks this would be hella cool, right? Spidey and Deadpool share a history in the comics, and the Merc's vulgar, violent approach would clash nicely with your friendly neighborhood Spider-Man. The jokes practicaly write themselves.
However, this is highly unlikely to happen because the Spider-Man movies are Sony properties. Marvel/Disney don't really get much out of those, so basically they would be giving Sony a free Deadpool movie. Things may be good between Marvel and Sony right now, but that's a bridge too far, I think.
The other two options on the table are to do Deadpool 3 as planned, or some other solo movie. Or they could go with a Disney+ limited series. Let's face it, Disney's not paying Ryan Reynolds' salary so he can do a streaming service, at least not until they get the most out of him on the big screen. They also want Disney+ to be a little more family-friendly and, despite Deadpool going PG-13 recently, I don't think now's the time for that to continue. When asked about Deadpool recently Feige responded "Why would we change it"? Good answer.
Fans would probably want to see Deadpool 3 most of all, but I don't see that happening, either. Feige is going to want to do his own thing with the character, so maybe a soft reboot that keeps Reynolds in the suit but begins a new story? Deadpool's bizarre, 4th-wall-breaking personality makes him perfect for a comical retcon. "Hey who are these F-list X-Men supposed to be? The Avengers...?"
This is way premature, anyway. There's no sequel to Spider-Man: Far From Home on the table yet, and probably won't be for quite a while. No matter what, you can bet Deadpool is going to make an impact on the MCU wherever he shows up.
