This one-shot revolves around a threat to the very existence of mutants in the Marvel Universe.
Marvel is gearing up for its annual one-shot that sets up the publisher's books for the coming year. If you're interested in what 2025 has in store for the Marvel Universe, Timeslide #1 is where you'll want to start. Starring Cable and Bishop, the issue will explore a threat to mutants that sounds an awful lot like the setup of a Terminator movie. Here's the synopsis from Marvel:
An X-Man from the future arrives in the present with a dire warning: One of mutantkind’s most hyper-advanced foes is eating his way through time, trying to stop the X-Gene from ever evolving in the first place. Only two X-Men can stop this chronal predator from achieving his goal – if they can tolerate working together long enough. Join Bishop and Cable on a trip through futures past, present and beyond.
"Hyper-advanced foes" isn't super specific, but surely fans will be scratching their heads and trying to sleuth out who this villain might be before the issue launches on Christmas Day. Timeslide #1 is written by Steve Foxe and drawn by Ivan Fiorelli, with a cover by Kael Ngu.
Source: Marvel Comics Press Release