When Hick did an interview with one of the writers for the game, after launch, I didn't get the impression that the game had any DLCs in plan unfortunately. And if they wanted to make them, they should've been on it and know of it by that point knowing how long things take to make.
Were they not expecting success, or was the game expensive to make, I don't know. But if Fireteam Elite is getting a sequel probably, this game deserves to get one as well. I wanna see these mechanics in more stories.