The Marvel Cinematic Universe has been spending every project since the end of The Infinity Saga to set up the concept of the multiverse. DC, quick to follow on Marvel's heels, is using the same in an attempt to reboot its lackluster cinematic universe. True to form, Marvel has taken a slow and steady approach. Titles like Loki, Spider-Man: No Way Home and Doctor Strange in the Multiverse of Madness established the rules of what the multiverse is and how different characters might interact with it.
Source：https://www.cbr.com/mcu-dcu-havent-nailed-multiverse/
