Who died?
Now, we already know that Spider-Man, Black Panther and the Guardians all have more movies in the works, which would be pretty hard to release if all of those characters are presumed dead. Filmmakers love a good prequel, but three prequels? There's no way.
If I was a betting woman, I'd wager that all of our heroes aren't actually dead, but have simply disappeared for awhile. Maybe they're on another planet, maybe they're in another dimension -- either way, they'll be back. We don't know for sure if Ant-Man was vaporized or not, but we do know that he has the ability to cross dimensions, known in the MCU as the Quantum Realm. In the Quantum Realm, both space and time are irrelevant. So if the rest of our heroes are trapped in another dimension following their tussle with Thanos, he may be able to reach them or even open some sort of portal between the dimensions to get them back.
Which brings me to my next question...
What's up with Captain Marvel and that cut scene?
In the scene following the credits at the end of "Infinity war," we see S.H.I.E.L.D. agents Nick Fury and Maria Hill get vaporized along with everyone else. Before he disappears, though, Fury pulls a device out of his bag and calls someone. We find out that he paged Captain Marvel, one of the many heroes from the Marvel Universe that we have yet to meet. Why did he call her? Well, because she may be the only person who could evade Thanos' scheme.
We know that when Brie Larson finally takes the screen in her role as Carol Danvers, aka Captain Marvel, her powers are going to be far beyond that of any other character we've encountered thus far in the MCU. Captain Marvel is part Kree (a scientifically and technologically advanced alien race), and is basically Superman on steroids. In the comics, her powers include superhuman strength, speed, agility, insane reflexes, flight, precognition (she can see a bit into the future), energy manipulation and healing. TL;DR -- she's pretty effing powerful.
Similar to Ant-Man, Captain Marvel has the ability to access the Quantum Realm. Unfortunately, she can't technically time travel (because that would make everything way too easy), but when combining all of her other powers, she can exist in space without any technological assistance.
A solo Captain Marvel film is currently slated for March 2019 and will be set in the 1990s to dig deeper into the origin of her power. She will also appear in "Avengers 4," which comes out just two months later. If I had to guess, I'd say "Avengers 4" will pick up right where "Infinity War" left off, and we'll see Miss Danvers answer Fury's call -- hopefully with Ant-Man in tow.
Why did Dr. Strange give Thanos the Time Stone?
A couple different things could have happened here that influenced his decision to give up the stone. In the winning outcome, he may have seen Tony alive and playing a crucial role in the eventual victory over Thanos. If that's the case, he knew that Tony needed to stay alive, not die on Titan with a stake through his heart. It's also possible that he saw Captain Marvel in the future, and he knew that sh*t would really have to hit the fan for Nick Fury to call her back from whatever dimension she's been living in. Maybe it's just me, but I'm fairly certain that Thanos filling the Infinity Gauntlet and eliminating half the universe is the definition of sh*t hitting the fan.
What happened to the Infinity Gauntlet?
As far as we know, Thanos may still have the stones. Also, just because the Gauntlet looked a little wonky when he went off on his power trip doesn't mean that Thanos doesn't still have it and/or the power to use it. In the comics, after half of the population is obliterated, it's actually Nebula who steals the Gauntlet from Thanos and uses it against him before restoring the entire universe to be the way it was 24 hours before -- thus bringing all of the Avengers back to life. The chances of the Russo Brothers following this storyline in "Avengers 4" are slim, but at this point anything is possible.
What's wrong with Hulk?
I think this character arc will come to some sort of a close in "Avengers 4," and we'll finally find out if these two guys can coexist without one of them leaving the other high and dry in the middle of the battlefield.