Okay, so we know that events in "Captain America: Civil War" will force groups of super heroes to choose sides and then go toe-to-toe over a controversial issues. We also know that Captain America and Iron Man will lead these respective sides in the conflict.
What we don't know is how rough that conflict will be for Robert Downey Jr.'s Tony Stark. Take a look at these pictures of Downey on set of "Civil War." Things don't appear to be going his way at the moment.
Stark/Iron Man has clear bruises and cuts on his face, hinting at a recent super powered altercation. However, we must remember that we have no context for this photo. Even though Cap looks to be getting the better of Iron Man so far, we have no idea of the details surrounding these facial injuries in the film. It's entirely possible that they are not the result of a fight with The First Avenger and, instead, are suffered at the hands of the film's villain.
In the comics, a tragic event spurred on by super powered villains and heroes causes the deaths of countless innocents. This leads to the government passing the Super Hero Registration Act which forces masked vigilantes to reveal their secret identities and work under government authority.
Captain America, ever the freedom fighter, believes this infringes on our civil liberties. The Marvel Cinematic Universe already planted this ideological seed in Steve Rogers thanks to the corruption and downfall of SHIELD in "Captain America: The Winter Soldier."
On the other side of the aisle is Tony Stark, who as we saw in "Avengers: Age of Ultron," is all too aware of the danger he and other super powered individuals are capable of. As such, he sides with the government. All of this leads to a bloody clash with far reaching implications.
Marvel fans can expect similar results in "Civil War" which will also mark the MCU debuts of Black Panther and Spider-Man.