The Hellfire Club was introduced to the big screen in 2011’s X-Men: First Class, but following the death of Kevin Bacon’s Shaw, it hasn’t been seen or referenced since in that universe (presumably it collapsed).
For those unfamiliar with X-Men comic book lore, the Hellfire Club was introduced in 1980’s Uncanny X-Men #129, and with the organization’s Inner Circle at the time consisting of Sebastian Shaw, Emma Frost, Harry Leland, Donald Pierce and Jason Wyngarde, a.k.a.
Still, Simon Kinberg decided to use Selene as a stand-in for the organization during this latest exploration of Jean’s fall from grace.