We may be only a few months into Phase 3 of the Marvel Cinematic Universe, but Marvel Studios and Disney are already gearing up for the end. While we sit and wait for Doctor Strange, the second of ten movies in this phase, to be released at the end of the year, by the time we are able to see it, production will already be underway for the end. It was previously announced during the Phase 3 announcement in 2014, that it would end with Avengers: Infinity War Part 1 in 2018, followed by Avengers: Infinity War Part 2 in 2019. That is no longer the case.
Disney has updated their upcoming release calendar and in doing so have revealed the official title for the followup to Avengers: Age of Ultron, while leaving the next installment unknown. Now, instead of the next Avengers film being Part 1 of the Infinity War story, it is the only part. The third Avengers film has been officially re-titled to just Avengers: Infinity War, while the one formerly known as Part 2 is currently Untitled Avengers.
This is an interesting move for many reasons. When directors Joe and Anthony Russo revealed they wanted to change the name, it was widely assumed that Part 2 would keep the Infinity War subtitle while Part 1 received something similar to Infinity Gauntlet or Thanos Quest. With this now being the case, it appears as if the war will be the focus of the next Avengers film, and that the untitled one could focus on something else. Make no mistake about it though, these are still very connected films that, while they have different titles, are very much connected. The plan is to still shoot these movies concurrently, so even though it is no longer Part 1 and Part 2, the overarching stories will still be tied together.
Avengers: Infinity War is scheduled to hit theaters May 4, 2018. Untitled Avengers is scheduled to hit theaters May 3, 2019.
Source: Disney (via The Wrap).