Spoilers follow for Marvel Comics' upcoming Secret Empire event as retailers have been given advanced copies.
Bleeding Cool got their hands on a copy of the retailer addition of Secret Empire #0, which is due to be officially released April 19th.
According to previous reports, retailers have been avoiding the pc-oriented Secret Empire series like the plague, so Marvel Comics has provided advance copes in order to get an increase in sales (whether it works remains to be seen).
Now on to the spoilers.
Kobic, the human Cosmic Cube, changed Steve Rogers to make him happier, which saw the Red Skull convince Kubik that Captain America would be much happier if he was an agent of Hydra.
However, Kubic just didn't change Captain America, she changed all of reality, in that Captain America has always been a sleeper agent of Hydra.
Now it's learned in Secret Empire #0, that Hydra was actually always at the head of the Marvel Universe in that Adolph Hitler really won WWII, but that the Allies used the Cosmic Cube to change reality to make the Allies win WWII and not Adolph Hitler.
So with Secret Empire really having it that in the Marvel comics universe, Hitler and Hydra really won the war (and that the Allies LOST), this further explains why Captain America would be happier (I guess).
So as noted, the entire Marvel comics universe is essentially: "What If Adolph Hitler didn't win the war?"
The good news is that it's also been reported Marvel Comics is ditching the political stuff and going back to basics.