Neversoft has worked on the past 3 CoD games in some way, shape, or form (their name has been in the end credits). For some reason, they are front and center along with IW and oddly Raven who also worked on the past 2 CoD titles. That's a first for a CoD title which I found odd, yet somewhat honest.
I believe Neversoft primarily did the Extinction mode this time around while in the past several games they made maps along with Raven. I'm sure they did some other stuff too but one of the press releases explicitly mentioned that they did the Extinction mode. --- "Cover your receptors Perceptor." Driver picks the music. Shotgun shuts his cakehole.