Marvel has made a small but important change to its film schedule: it's still planning to release Avengers films in 2018 and 2019, but they'll no longer be two parts of the same story. The first film will keep the title Avengers: Infinity War, but the second picture is now untitled, dropping its previous Infinity War — Part II moniker.
The studio didn't elaborate on what this means for either film's story. More than likely, the change means they'll be a bit more disconnected than they were originally planned; but, these being Marvel movies, they'll of course have a central through line, so it's not like they'll be entirely disconnected either.
Everyone hates two-parters
Overall, it's probably a good decision. People have been tired of the Part I / Part II thing basically since the day it started in the Harry Potter film series, and at no point has it really worked out well — Hunger Games' final films, for instance, weren't received as well as prior entries. And the first part of Mockingjay was criticized for feeling, well, like only half of a story.
This is apparently something the films' directors, the Russo brothers, have been discussing for a little while now. Entertainment Weekly points out that, back in May, one of the brothers said the two pictures are "very different movies" and that a name change was in the works. "We just haven’t come up with the titles yet," he said.
Apparently, the Russos still don't have a new title, but for whatever reason, Disney and Marvel have decided to make it clear that their plans are changing. Release dates, however, are staying the same as when the films were first announced, with Infinity War coming May 4th, 2018 and the fourth Avengers film coming on May 3rd, 2019.