This concern about being too spoiler-y obviously wasn't an issue when the Phase Three slate was announced, as Avengers: Age of Ultron and Ant-Man hadn't come out yet to conclude Phase Two. This time around, though, it's a bit different. The end of Phase Three will also wrap up a lot of loose ends from the previous 11 years. Essentially, Phase Four is being looked at as a new beginning for the MCU. It will be a way to hit that refresh button while still keeping continuity intact. While Avengers 4's plot hasn't been disclosed yet, Avengers: Infinity War will see the eponymous superhero team and other heroes from the MCU teaming up to battle Thanos. Surely some leftover threads from there will factor into the fourth Avengers flick and the Phase Three conclusion, right? Keep in mind that both those movies could also see major casualties, and Kevin Feige presumably doesn't want to spoil who will bite the dust.