The Wrap has revealed that Avengers: Infinity War will now "exist as one movie" after confirming with Disney that they've updated their release schedule. Avengers: Infinity War (previously titled Avengers: Infinity War - Part I) is the official title of the next instalment, while Avengers: Infinity War Part II has now become "Untitled Avengers." Both of them will still be released in 2018 and 2019 as planned.
Of course, just because Avengers: Infinity War is now one movie, that doesn't mean that the team's battle against Thanos won't still unfold over both instalments. Still, it's worth bearing in mind that the Russo Brothers have previously said that these are going to be two standalone stories rather than a single one handled the same way as when The Hunger Games and Harry Potter franchises wrapped up.
More details will hopefully be revealed soon, but for now, we do at least know that the next installment will simply be titled Avengers: Infinity War. But what will the 4th installment be called?
Avengers: Infinity War arrives in theaters May 2018. Avenger: TBT opens in theaters May 3, 2019.
http://www.thewrap.com/marvel-surprise-avengers-infinity-war-wont-be-split-into-2-movies/