"Avengers: Infinity War" will be the conclusion of Marvel Cinematic Universe's Phase 3 and if the reports are right, it may be the end of the current Avengers.
Phase 2 just ended and if you may recall, it did quite some damage to the Earth's mightiest superheroes. With Thor realizing in "Avengers: Age of Ultron" that the Infinity Stones are appearing in suspicious circumstances and a mid-credit scene showing the mad titan Thanos, it seems that the Avengers are going to face its toughest foe yet. So tough that it would be divided in a two-part movie.
As reported by IGN, a featurette on the "Age of Ultron" home video described what the Infinity Stones are and why they are the most important artifact in the Marvel Cinematic Universe.
According to executive producer Jeremy Latcham, the two remaining stones that has yet to be revealed (Time Stone and Soul Stone), will serve as the culmination of the Marvel Cinematic Universe.
Regarding when those two will appear, Slash Film asked Marvel Studios head Kevin Feige and said, "You will see the other two, sometime in phase three for sure. There's a gauntlet that needs to be filled."
In a related report by Comic Book, Latcham and Feige spoke about the current roster of the Avengers and how this roster, who helped launch this franchise may be disbanding.
Asked whether "Avengers: Infinity War" would be the end of the Marvel Cinematic Universe or the beginning of Phase 4, he said, "It definitely is an end to some version of the team that we've come to know in The Avengers. Who knows exactly what's gonna happen yet in that film but I think this version of that team, and I think we hint to it at the end of Age of Ultron, that the team will be evolving."
He further added "You know? It's not the end of the Marvel Cinematic Universe but I think it's the end of part of it, for sure. We're still trying to sort out which parts."
Avengers: Infinity War Parts 1 and 2 will come out in 2018 and 2019 respectively.