So the multiverse has been touched upon or at least alluded to in the following releases:
- Endgame (Ancient one; Steve Rogers)
- Loki
and is clearly a major part of:
- Spider-man No Way Home
- Doctor Strange in the Multiverse of Madness
- Ant-man and the Wasp Quantumania
It's clearly a major part of Phase 4, and they're obviously putting a lot of thought into how they handle it. I wonder to what extent existing, pre-Disney film properties will be incorporated (pretty strong rumours for Spider-man, but I'd like to know about X-men). I also wonder what this means for what the big bad threat for Phase 4 will be - is it Kang? Is it leading to Secret Wars-style clash of the multiverses? Thanos only showed up in the 6th MCU film, and didn't really culminate as the central baddie right until the end with Infinity War/Endgame, so I wonder how long they keep their powder dry for the next main villain, and if Phase 4, 5, 6,.... will be a 20+ film endeavour like the the Infinity Saga was.