While he would not reveal when the fourth film will be titled, Marvel Studios head Kevin Feige did explain the reasoning behind the change further.
It’s a whole movie and a whole story, and then a whole movie and a whole story.
For viewers this means that the ending to Infinity War should be a satisfying one as it completes that story, but still leaves threads hanging for the next installment.
The fun about those two movies that we’re doing essentially at the same time is everybody’s there.