When Marvel Studios decided to release a series of movies based on its main characters such as Captain America or Iron-man, they used the term MCU or Marvel Cinematic Universe to refer to this repertoire of productions that take place in the same universe, that is, the characters of these films that seemed independent of each other and are part of the others at the same time.
The MCU also includes TV series such as Marvel’s Agents of Shield, Agent Carter, Netflix series like Daredevil or Luke Cage and it is expected to include some series that would be released by Disney+, such as Moon Knight or She-Hulk very soon.
As part of a strategy to separate the films and give them a certain order, Marvel began to refer to a certain group of films as parts of a certain “phase” that encompasses a certain stage in this global history. For example, the Infinity Saga could be said to develop the history of the Infinity Stones which in turn is based on the Infinity Gauntlet comics. These cover the first three phases of the MCU.
Phase 1, also called Avengers Assembled, encompasses films that primarily featured certain superheroes (essentially the most important), as Nick Fury formed the group called The Avengers and revolved around the Tesseract, one of the Infinity Stones. This includes the first two Iron-man movies, the first Captain America movie, the first Hulk movie and the first Thor movie as well as the first The Avengers film.
Phase 2 focuses on developing the story of The Avengers and its relationship with the criminal agency HYDRA as well as a platform to introduce some new characters such as Winter Soldier, Ant-Man or Vision and provide more information about the Infinity Stones. In addition to those already mentioned, Captain America: The Winter Soldier and Ant-Man, phase 2 of the MCU consists of Iron-Man 3, Thor: The Dark World, Guardians of the Galaxy and concludes with Avengers: Age of Ultron.
Phase 3 covers a time of conflict and separation between The Avengers that is clearly reflected in Captain America: Civil War. It was also used to introduce new characters such as Doctor Strange, Captain Marvel or Black Panther as well as continue developing stories such as those of Ant-Man (Ant-Man and the Wasp) or Thor (Thor: Ragnarok). In addition, it served as the opportunity to introduce one of the best known characters (perhaps the best known) to the MCU, Spider-Man (Spider-Man: Homecoming). In this phase, the history of the Infinity Stones reaches its climax thanks to the strength that Thanos gained, mainly shown in Avengers: Infinity War and that is concluded with Avengers: Endgame. Spider-Man: Far From Home is also part of Phase 3, though it serves as more of an epilogue.
Marvel has already announced some films that will be part of phase 4, which will be the first after the Infinity Saga and even be encouraged to mention some for a possible phase 5. In 2019’s San Diego Comic-con, Marvel took the time to present films such as Thor: Love and Thunder, where Natalie Portman’s return is expected as the first female Thor in the MCU, the first Black Widow solo film or the ones with less information, such as The Eternals. Shang-Chi and the Legend of the Ten Rings, Doctor Strange in the Multiverse of Madness and some of the series such as Loki, Wandavision, The Falcon and the Winter Soldier were also announced.
At this point, the Infinity Saga is over and seeing the announcements made by Marvel, it is a bit unpredictable what will be the path that they will take in this new phase which has given rise to many assumptions like, for example, who will be the new villain or who will be the new leaders of The Avengers after what happened in Endgame.