The Quantum Realm was first introduced in Ant-Man, when Scott Lang entered the alternate dimension where time and space are irrelevant.
It next appeared briefly in Doctor Strange before being explored further in Ant-Man and the Wasp.
In fact, as Thanos’ Snap happened, Scott was trapped in the Quantum Realm.
While the realm is set to play a further part in Captain Marvel and Avengers 4, insiders are now claiming it will be the future of the MCU.
Hollywood writer Daniel R tweeted: “The Quantum Realm is the future (of the MCU).”
While Jeremy Conrad, who leaked the alleged Avengers 4 title, replied: “THIS. There is a lot they’re doing with the Quantum Realm beyond just Ant-Man.
“They can just put ‘Quantum’ in front of Phase 4 and call it the Quantum Phase.
“Ant-Man and The Wasp is just the start of many fantastic voyages into the Quantum Realm in the MCU.”
He added: “There really is no plans for the next one [Ant-Man 3], but you can’t help but talk as filmmakers and creative people about where you would go next if you ever got the opportunity.
“And we talk a lot about the Quantum Realm and there would be perhaps more opportunity to go down there.
“Maybe there’s more down there than we realised. Clearly, Janet’s been up to something and has different clothes on and some weapons. Where did those come from?”
Avengers 4 is released in UK cinemas on April 26, 2019.