Gambit might have more than one adversary in his upcoming solo film, but it's probably not the one you're thinking of.
The spinoff film has moved around quite a bit on the schedule, but it seems things are starting to move in the right direction. A recent casting breakdown seems to indicate a callback to the comics, one you might not expect. The casting breakdown obtained by That Hashtag Show reads "Supporting Character (30-40) Rosa’s fiancé,
That could be a few people, but the "Rosa's fiance" and "villain" terms are key. Going by those the film could be casting for a Mr. Donyell Taylor, who you might know as Bandit or the second Night Thrasher. Donyell is Dwayne Taylor's half-brother, who is the New Warrior's original Night Thrasher. Donyell would eventually run into Gambit's ex-wife Belladonna Boudreaux, and the two would date until Gambit interferes in Belladonna's best interests.
The film is rumored to feature Mr. Sinister and a number of Assassins for Remy to face, so it isn't a stretch to think that Donyell (or someone like him) could figure into the storyline. Donyell would likely be an early foe for Gambit to tackle (especially with that villain tagline) before Mr. Sinister and would play well with the Oceans Eleven Romeo & Juliet vibe that the project is rumored to be going for.
Gambit has been in development for some time and has gone through its share of directors. Throughout all of it though Channing Tatum has continued to be attached, and it seems that patience is finally starting to pay off. Gambit will be directed by Gore Verbinski and is set to start shooting in March.
Gambit currently has a 3.49 out of 5 on ComicBook.com's anticipation rankings, which you can vote in here.
Gambit has a tentative release date of February 14, 2019.