At 2:00 you see Hulk running with Black Widow, Captain America, Black Panther, Bucky and others. War Machine and Falcon flying with them
And at 0:26 is Banner working on some new Hulkbuster armor? Prediction: He's building it for himself, so he can fight without turning into the Hulk. But that is only going to delay the inevitable.
I figure he uses it to fly to Wakanda since he's in NY. The suit even lands (visually) like Hulk does if that makes sense.
I'm guessing we'll finally get that rumored scene where the Hulk bursts out of an Iron Man suit in a surprise attack.