X-Force is a fictional Marvel Comics superhero team, one of several spin-offs of the popular X-Men franchise, and the eponymous subject of the X-Force comic book series. Conceived by writer/illustrator Rob Liefeld, the team was formed in New Mutants, vol. 1 #100 (April 1991) and soon afterwards was featured in its own series.
The group was originally a revamped version of the 1980s team, the New Mutants. Led by the mutant Cable, X-Force was a more militant and aggressive group compared to the X-Men. The X-Force series was successful in the early 1990s, but its popularity waned after Liefeld left, which caused Marvel to implement several reforms to the title from 1995 until 2001 with varying degrees of success.
Low sales on the X-Force series eventually prompted Marvel to revamp the title in 2001 with a new cast in the form of a group of self-interested young mutants who were gathered together by a corporation to become media stars and used the name X-Force. X-Force, vol. 1 was canceled with #129 and relaunched as X-Statix, which coincided with a similar rebranding of the team in the story. After X-Statix was canceled with #26, Marvel reunited the original X-Force team for a six-issue 2004 miniseries plotted and drawn by Liefeld.
In 2007–2008, during the Messiah Complex crossover, a new version of the X-Force team was formed with Wolverine leading a more militaristic black-ops branch of the X-Men. This squad would form the basis for a new X-Force series starting February 2008 by writers Craig Kyle and Christopher Yost, plus Clayton Crain as the artist. The series came to a conclusion in September 2010 as part of the Second Coming storyline that ran through various X-titles. The title was then relaunched in October 2010 as Uncanny X-Force with Rick Remender and Jerome Opeña as the creative team and Wolverine, Psylocke, Deadpool, Archangel, Fantomex, and E.V.A. as the initial roster.
The Uncanny X-Force series ended at issue #35 in 2012 was once again relaunched as Uncanny X-Force vol. 2 as part of Marvel NOW!, with a new team led by Storm and Psylocke written by Sam Humphries. A concurrent X-Force book written by Dennis Hopeless, Cable and X-Force, was released at the same time, bringing Cable back into the X-Force fold. The two series ended in 2014 after a crossover between the two titled "Vendetta". A new X-Force (vol. 4), was launched featuring a black-ops squad composed of Cable, Psylocke, Fantomex and Marrow, written by X-Men: Legacy writer Simon Spurrier.