The 'Deadpool' mastermind is toying with writing treatments for a film that would feature three or four members of Marvel's mutant team, but has not yet pitched an idea to the studio.
I really enjoyed Deadpool and Wolverine, as a sort of fond farewell to the 20th Century Fox Marvel movies, but I don't have any desire for this. Especially, as Jake notes, when we haven't got the MCU version of the X-Men yet.
It doesn't sound like this is anything official though, just something Reynolds is working on to potentially pitch to Marvel at some point.