There's a new map for Call of Duty: Modern Warfare 3 coming. It's called "Overwatch" and it will be available to Premium Members on the Xbox Live online entertainment network on February 21.
Here's the official description:
"Call of Duty Elite Drop 3: Overwatch drops you into a construction site atop a New York City skyscraper. The battle takes place along two levels in a near symmetrical layout, with the central bridge and side routes open to attack from multiple angles. Watch your every step, as a lack of safety barriers surrounding the perimeter leaves nothing between you and a 70 story fall to the ground below."
Overwatch is the third "Content Drop" in Modern Warfare 3’s Content Season, which will include more than 20 pieces of new content over nine months. Elite Drops 4-6 will be available in March for Premium Members on Xbox Live and will include the multiplayer map Black Box and two brand new Special Ops Missions, Black Ice and Negotiator. The full calendar of content is outlined here