This is a teaser for a new mobile game starring, at the very least, Marvel's The Avengers. I'd love to tell you more, but they call it a "teaser", and not an "explains everything in 40 seconds", for a reason.
I'm really sick of "The Avengers" being the cinematic Avengers. While I do appreciate the appearance of Hulk and Hawkeye, it would be better if they stayed faithful so that other heroes can get the spotlight. Ant-Man, Black Panther and Ms. Marvel are all my favorite heroes and I hate when they get shafted for Black Widow and non-brash Hawkeye just because of recognition.