Call of Duty isn't afraid to fall back on famous actors to bad guys, especially in recent years. Kevin Spacey did it most famously in Advanced Warfare, and last year, Christopher Meloni got in on the action in Black Ops III.
Infinity Warfare seems to be going the same route. They've gotten Kit Harington in to play what looks to be the bad guy in the game. It was revealed in this video tweet, showing the actor getting ready for a mo-cap performance.
— Call of Duty (@CallofDuty) June 10, 2016
Narrative director Taylor Kurosa said:
Our story is about an epic showdown of opposing forces, and Kit immersed himself into the role and truly became the embodiment of the enemy, the Settlement Defense Front. We can't wait for fans to see Kit play an entirely different kind of character.
It seems that Guy Ritchie, who has a history with the franchise is involved too, but it's not really clear exactly what he is doing. It is said he helped in "assisting in bringing Kit Harington's character to life in Infinite Warfare", but that was the extent of it.
All interesting, and Harington as a pick for the main bad guy feels a little left field. Certainly in to see what he brings though.