Channing Tatum is not officially set to play Gambit yet, but it looks like that's what things are leading too. In an interview with MTV the actor talks about the development of Gambit, and says that he wants to try and change the superhero movie.
"Creatively, we're starting to chug forward. Obviously there's nothing [official]. There are only conversations and dreams right now, really."
Tatum goes on to explain that we'll probably see a stand alone Gambit film before he joins the rest of the X-Men team. He also talks about trying to "change the superhero movie" saying:
"We've talked about it being a standalone, first, and actually trying to change the 'hero, superhero movie.' Because Gambit is not your typical hero. He's a thief. He walks on the gray. I'm hoping we can change it a little bit, and then ultimately feather into the other ones."
As of right now, there's no writer or director that have been attached to the project, but there's always the possibility that Gambit could be the "Untitled FOX Marvel Movie" which is currently set for release on July 18, 2018. I'm sure we'll find out soon enough,