Xbox Wire : FBC: Firebreak is not Control DLC and its definitely not a Control sequel.
Game Director Mike Kayatta is forthright when it comes to his new game.
Were actively avoiding coming even close to feeling like either of those things. I guess you could say that its a spin-off, but in the most positive sense of the word. Its not designed to be some kind of lesser, bite-sized Control. FBC: Firebreak is its own, fully formed thing.
Source: N4G PC Xbox Partner Preview | FBC: Firebreak Learn More About Remedys First Ever Multiplayer Game