A couple of days ago Infinity Ward released a new Call of Duty: Ghosts trailer showcasing the new “Squads” mode where human players lead a team of bots against one another. In the trailer viewers have spotted an unannounced game mode called “Extinction”, mentioned in the top right-hand corner at around the 0:24 mark.
Infinity Ward hasn’t revealed as to what the Extinction mode is but players are speculating over some kind of ‘Zombie mode'; specially after a leaked listing of the game’s nine secret Achievements mentioned achievements like:
No Man Left
Escape with all four players.
Reach the exfil chopper with 1 minute and 30 seconds or more remaining on the clock.
Made it Out Alive
Escape 1st time.
Complete all Extinction challenges and escape.
Make it to the Cabin.
Made it to the city.
Any Means Necessary
Get 50 kills with the electric fence and fire traps in a single game.
Scavenge 40 items in a single game.
Escape using a relic.
At first, some of them were thought to represent the final stage of the single-player campaign where the player is perhaps to escape a compound or something similar. However, with the mention of “Extinction” it seems more like an answer to Treyarch’s Zombie mode in Black Ops II.