We were first introduced to S.H.I.E.L.D. in 2008's Iron Man, but the spy organisation didn't really step into the spotlight until The Avengers rolled around in 2012. However, two years later, S.H.I.E.L.D. fell in Captain America: The Winter Soldier, and that was it (unless you count Agents of S.H.I.E.L.D.).
As for HYDRA, they were put to rest by Earth's Mightiest Heroes in Avengers: Age of Ultron's opening sequence, a shame when we're talking about a villainous group with a tonne of potential on screen.
During today's global press conference for The Falcon and The Winter Soldier, Marvel Studios President Kevin Feige was asked if the two organisations could return to the Marvel Cinematic Universe.
"Well, again, you can always look at the comics, right? We always take our lead from what has happened before, and those organisations come and go in various forms over the years," he teased. "So, they always could [return]. There are new organisations like S.W.O.R.D., that you saw in WandaVision, so there's always an inherent need for above-board or shadowy organisations of some kind in the MCU."
It would be cool to see more of S.H.I.E.L.D. and HYDRA in the MCU, but as that mention of S.W.O.R.D. indicates, there are definitely other heroic and villainous groups which can be the focus now. S.W.O.R.D. is a natural next step for this shared world after the events of Avengers: Endgame, while many fans are convinced that A.I.M. is about to step back into the spotlight in this series.
In other words, we could be waiting a while before an evil Captain America utters "Hail HYDRA!"
The Falcon and The Winter Soldier premieres on Disney+ this Friday, March 19th!