I think in flashbacks or in Carrie’s dreams. (prefer the former)
Almost every interview this year there are questions about Brody’s return, and the answer remain the same: It’s definitely an option.
Since Damian is shooting Our Kind of Traitor right now, I don’t expect to see him early this season. My bet is on 410, where he will make a special apparance. (We’ll have confirmation when he goes to South Africa.)