Couple of questions I want answered:
-When we last saw them, Tony and Nebula were on Titan. Why would they get on a ship to get off Titan if they weren't able to reach Earth, and why could Nebula not pilot them there?
-Where's Valkyrie? She was announced to be in IW and then never showed up. Will Thor recruit her from wherever she is to help fight Thanos for round 2, and when she sees Banner, will she refer to him as Beast?
-How does Earth treat Rocket, a sentient raccoon?
-Why can Thor not Bifrost to Titan and go scoop up any remaining survivors? They know where they are, and if not, Wong could help.
My predictions for the movie:
When Tony gets back to Earth, he and Shuri kit out the whole team. He makes Shuri some sort of "Iron Panther" suit, since the lack of heart shaped herb means she can't take up the powers her brother had. Before he dies at the end of the film, Tony's consciousness gets turned into an AI that goes into Shuri's suit, she's been RiRi all along, we get a movie of her fighting some sort of crime in Oakland.
Something happens to awaken X-Men. We see a brief flash of a girl that will later be Kamala Khan, whose origins they've changed from Inhuman to Mutant.
Cap dies as well, Bucky becomes a new Captain America (aka Patriot).
Korg is on the new Guardians team at the end of this movie. He was with Valkyrie (and the last remaining Asgardians), but they both get recruited during this film. Valk goes off with Thor and Korg goes off with Rabbit.