With the Multiverse Saga nearing it's end with Avengers: Doomsday and Secret Wars, the next saga is already close. With Disney's acquisition of Fox and it's rights to Marvel characters like the X-Men, it is likely the next Saga will focus on the mutants. It could be named The Mutant Saga, but if the Phoenix Force comes into play The Phoenix Saga would be an apt title as well. However, the world of the MCU is also still occupied by the Avengers and other superheroes. So, here's a look at what the trilogies, titles and release dates could look like.
Spider-Man: The City That Never Sleeps
The next Spider-Man movie, Spider-Man: Brand New Day (2026), follows Spider-Man as he works with the DODC to incarcerate street level villains like Scorpion and Tombstone. The relationship turns sour when Jean Grey enters the fray. Jean even unleashes the Savage Hulk, but Spider-Man manages to beat all of them. In the end, Jean sees the error of her actions and leaves for north New York. Then, Spider-Man: The Next Day (2029) follows Spider-Man fighting Kraven, Agent Venom, Mr. Negative and eventually Knull. Peter also meets Miles Morales, who ends up gaining powers too.
The trilogy comes together in Spider-Man: One Last Day (2032). As Peter teaches Miles his newfound powers, Kingpin returns. He has the Thinkerer equip the Vulture, Scorpion, Mysterio, Shocker, and Hobgoblin (a corrupted Ned Leeds), and forms the Sinister Six to fight the Spider-Men, Daredevil and a defected Black Cat. Outside of this, Spider-Man will most likely return Avengers: Secret Wars. That movie could even see him unite with the other live-action Spider-Man in a Spider-Corps, similar to the Thor Corps from the eponymous comics. Moreover, Spider-Man (and She-Hulk) could join and the Future Foundation too.
X-Men: The Mutant Saga
The saga could kick off with Uncanny X-Men (2028). It follows Cyclops, Marvel Girl, Angel, Beast Storm and Rogue as they face Mr. Sinister and Emma Frost. It turns out Sinister plans to use Cyclops and Marvel Girl to prepare for a future threat and reveals their existence to the world. With mutants now out in the open, the X-Men are attacked and abducted by Sentinels in Giant-Size X-Men (2033). Only Cyclops remains, who recruits Bishop, Wolverine (introduced in his own tv show), Banshee, Sunfire, Colussus, Nightcrawler and Thunderbird to defeat the Sentinels and free the abducted mutants.
The Celestial threat Sinister has warned off finally arrives in Astonishing X-Men (2038): Apocalypse. Both the Blue and Gold teams work together with the time-travelling Cable to stop him. The fight ends when Jean lets the Phoenix Force take over to defeat Apocalypse, only to flee into space after. X-Factor, a companion tv show, could expand on the school's students like X-23, Polaris, Havok, Shadowcat, Psylocke, Dazzler, Gambit, Jubilee, and Magik and villains like Magneto's Brotherhood and the Hellfire Club and, while Starjammers focuses on threats from space and Excalibur on MI-13's adventures.
Avengers: World's Mightiest Heroes
The next Saga could start with Avengers: Annihilation (2032), where Annihilus is coming for Earth. It's up to Nova, Captain Marvel, Thor, Hercules, Rocket's Guardians of the Galaxy, the Eternals and the Fantastic Four to form a united front against the coming attack. Annihilation could serve as conclusion to the arcs of Captain Marvel, Thor and Rocket. Following this is Avengers: Korvac (2037), where Michael Korvac is empowered by the Celestials and uses that power to conquer Earth. The new Avengers unite to face Korvac and ultimately defeat him with the Eternals' help.
Finally, the Saga comes to a close with Avengers vs. X-Men (2042). When Jean returns to Earth, the Avengers confront her when learning from the pursuing Shi'Ar the threat she poses. This leads to a clash with the X-Men during which Jean succumbs to the Force, splitting it in five parts. It merges with different X-Men, including Cyclops, and in the following year they reform the world. Following this regime change, the Avengers and X-Men once again come to blows as the Phoenix Five's power grows unchecked. The conflict ends when the young mutant Hope absorbs the Force.
Meanwhile, on the tv side Thor, Captain Marvel and Hulk fend off the Dark Avengers -Norman Osborn, Hercules, Abomination and Zemo- attacking New Asgard in Dark Avengers, while Midnight Sons, Young Avengers and West Coast Avengers form the Mephisto Saga. The teams are taking on Dracula's daughter Lilith, Lilith and Mephisto's son Blackheart, and finally Mephisto himself respectively. Movies that will be released in this saga as well are Doctor Strange in the Dimension of Darkness, Ghost Rider, Black Panther 3, a Nova trilogy, Shang-Chi 2 & 3 and Fantastic Four 2 & 3.