Note: There will be some spoilers from Extermination.
The X-Men have recently suffered a loss. During the events of Extermination, a mysterious figure was hunting down the original time-displaced X-Men. During this mission, the figure turned his guns on the X-Man that stepped in to save young Iceman from being taken. It resulted with a brutal death that was telepathically felt by Jean Grey.
The fallen X-Man will be mourned in the upcoming X-Men: The Exterminated (details can be found here). The character who was killed was Cable. With his death, X-Force will get back together to fight in his memory.

Marvel has announced that Ed Brisson and Dylan Burnett will be the creative team on a new X-Force title. Domino, Cannonball, Shatterstar, Warpath, and Boom Boom are looking for revenge. They intend to track down Cable’s killer. The fact that Cable’s killer is a time-traveling younger version of Cable, you can imagine things will get a bit complicated. How far will the team go for revenge?
In an interview with Marvel, Brisson mentioned X-Force is a team that is willing to do things others in the Marvel Universe will not. The team is angry and confused. They need answers as to why Cable was killed.
‘They’re on the hunt for this new Kid Cable to get those answers—some want his head, some just want to talk to him to find out what the hell is going on. Is this really their Cable? Is this an impostor? We’re going to learn more about Kid Cable and establish what sets him apart for the Cable that people know. We’re going to get into his history and have some really exciting stories cooking with a laundry list of X-Force villains. There are layers to be peeled back, but nothing is what it initially seems.’
We’ll have to wait until December 26 to get some of those answers.