Yep…that’s a trailer!
And so what you pretty much have here is “THE MOST EPIC MOVIE EVER MADE!!!!,” ten years in the making. In a way, despite the tremendous recent success of Black Panther, it’s kind of a “bookend” to the interlocking Marvel Cinematic Universe films, an era launched by Iron Man in 2008.
Let’s face it: this may very well be the end-of-the-line for Robert Downey Jr. as Iron Man and Chris Evans as Captain America. It’s not tragic: they had an amazing run.
If I had to guess, those two are going to exit during/after Infinity War, with Bucky/Winter Soldier (a.k.a. “White Wolf”) taking over as Cap (which I believe had happened in the comics as well way back when)—though it could also be Anthony Mackie/Falcon who takes over the role.
You definitely get the ominous feeling at the end of that trailer with Cap/Thanos that the former is “going down.” You’d probably have Iron Man or Cap dying earlier in the movie (maybe like in a “shock” way), setting up that big climax in the end where they all literally “Avenge” him.
Don’t see Chris Hemsworth as Thor really going anywhere, and many of these other characters are pretty “fresh” (Dr. Strange, Spider-Man, Black Panther, etc.). Scarlett Johansson as Black Widow is a tossup. If Tom Hiddleston really didn’t want to play Loki anymore, I’m sure he might do a “heroic death” type thing.
Anyway…very much a “next generation” vibe, passing on the torch.
That’s my thoughts. Not “The End,” just the end of an era.