Yesterday, Marvel unrolled their plans for "phase 3" in their long haul of successful comic movies. According to Marvel, phase three will culminate in an epic, two-part Avengers movie titled, Avengers: Infinity War. And you can watch the teaser trailer now!
This "announcement trailer" is what Marvel released during their press day. Obviously this isn't footage from the actual movies, but the implication is obvious. Thanos has the Infinity Gauntlet, with all six infinity gems (the stones you've seen people collecting in various after credits scenes in Marvel movies) and now he's indestructible.
And here's another look at Thanos brandishing the ultimate weapon. Avengers: Infinity War will be released on May 4th, 2018, and May 3rd, 2019. Expect big, big things to come out of these movies. And by "big" we mean a lot of death.