Apparently that is what is already going on with Ant-Man and Wasp.
"Those characters are experts in the quantum realm. In
Ant-Man and the Wasp, they are trying everything in their power to safely enter the quantum realm and return back from it because they have evidence from the first film that Scott Lang was able to do that.
"If he can do it, why can't we?
If we do succeed in Ant-Man and the Wasp, then that does open a whole entire new multi-verse to enter into and play around in. I'm not the story creator, so I can't tell you what they're going to do with that. But I definitely see the potential there."
Ant-Man and Wasp plot detail leak could change the MCU