Last I heard it was revealed in the comics that Cap belongs to Hydra and has all along...
Yea. The Marvel Universe has so many competing branches and trails it’s gone down you can say that about any of them, but nothing is concrete.
For example, just how many Captain Americas, Directors of SHIELD and Avengers (new, old, complete, etc.) have there been?
At least ten different Captain Americas beyond Steve Rogers.
And no one seems to die forever! Need Hawkeye back? No problem! The Scarlett Witch just dreamt his death! (House of M).