In addition to introducing characters like Scott Lang, Hope van Dyne and Hank Pym to the Marvel Cinematic Universe, 2015's Ant-Man was also notable for introducing the Quantum Realm, an alternate dimension that can be accessed when someone shrinks to microscopic levels. Thanks to Doctor Strange, we now know that the Quantum Realm is one of numerous other realities that exist within the MCU. Now it turns out that in addition to its importance in the Ant-Man movies, the Quantum Realm will also play a role in the upcoming Captain Marvel, specifically with understanding the heroine's place in the MCU.
While Dr. Spiros Michalakis, a quantum physicist who consulted on Ant-Man, wasn't at liberty to reveal too much about on he knows about Captain Marvel, he did hint that this reality will tie into the 2019 Marvel blockbuster. He told Inverse:
Spiros Michalakis also commended the MCU on how they've "described the multiverse" so far, noting how these other realms exist concurrently with our reality. While Ant-Man laid the foundation for the multiverse, it was Doctor Strange that fully pulled the curtain back on that concept, as one of the many things Stephen Strange learned while studying sorcery at Kamar-Taj was how to travel to other realities. With the MCU's multiverse established, it opens up even more creative routes to go down, and it looks like Captain Marvel will take advantage of that.
Although there's speculation that a non-powered Carol Danvers could debut next year in Avengers: Infinity War, her superhero origin story won't unfold until Captain Marvel. In the comics, Carol gained her abilities when she was shielded by an alien energy detonation by the Kree operative Mar-Vell, and she was subsequently turned into a human/Kree hybrid. Writer Nicole Perlman said last year that Carol's origin will be changed for the Captain Marvel movie so that it doesn't resemble Green Lantern's as much, so perhaps turning to the Quantum Realm is the key to distinguishing her live action counterpart from the Emerald Knight.
No Captain Marvel plot details have been released yet, but Nicole Perlman is tackling the script with Meg LeFauve, and Anna Boden and Ryan Fleck were hired as the directors last month. Before Carol's superhero journey begins, most of the Ant-Man gang is returning next year for Ant-Man and the Wasp, and since Han Pym's wife, Janet van Dyne (the original Wasp), was lost to the Quantum Realm decades ago, perhaps the sequel will explore this strange dimension again before it plays into Captain Marvel.
Ant-Man and the Wasp will be released on July 6, 2018, and Captain Marvel will fly into theaters on March 8, 2019.