It's an AU. Not the same one as previous Marvel Zombies stories though. If it was in continuity, then Gamora wouldn't have been one of the GOTG reps (as she's no longer on the team) and Wu, Korr, and Vil wouldn't have been with the Fantastic Four (the Future Foundation don't even know the F4 are now at 4 Yancy Street in 616, as they're still off world).