Huge blockbusters always have a working title, which is meant to keep the fans off the track for as long as possible - after all, if a fan doesn't know what he's seeing, he will never tell anyone. In the case of Captain America: Civil War, the working title is Sputnik.
If it seems peculiar, then compare it to the working title of The Avengers (Group Hug) or Captain America: The Winter Soldier (Freezer Burn). It doesn't sound so strange right now. Right?
Why Sputnik?
The first thought when hearing this name would be about the first Soviet mission into the outer space. But this isn't the case - and, as you might have expected it, the word Sputnik appears on several occasions in the comic books.
For example, this was also the name of a low-tier villain and enemy of Captain America - but we believe that this has little to no importance for Captain America: Civil War.
Usually (and as you might have guessed from the working titles of The Avengers and Captain America: Winter Soldier), the working title does reveal something that we will see in the actual movie.
What does Sputnik reveal for Captain America: Civil War?
Sputnik is also a code - namely a shutdown code assigned to the Winter Soldier by the Soviets. And this shutdown code was used only once in the comics - and this is where things get interesting.
Now we know that during the Civil War we will see Iron Man going toe to toe with Captain America - but, until now, we didn't know how things will end (even if we had a good idea if we were looking at the comic book origins).
Sputnik was the shutdown code used against the Winter Soldier (Bucky Barnes, as we all know, the friend of Steve Rogers, aka the first Captain America) when he went berserk after Crossbones and Tony Stark's Mighty Avengers.
What caused the wrath of Bucky Barnes?
We might have guessed it before, but now it is almost clear - this shutdown code was used only after the death of Steve Rogers.
And now, we believe, everything is pretty clear - now Captain America: The First Avenger, Captain America: The Winter Soldier and Captain America: Civil War form the strongest and most organic story-arc in the entire Marvel Cinematic Universe.
If Sputnik does suggest what we believe, then the end of Captain America: Civil War will shatter the MCU and lead to the creation of a different team of Avengers, with Bucky Barnes as the new Captain.