Spider-Man: Across the Spider-Verse is finally in theaters, exploring the multiverse even further than ever before. While its 2018 predecessor introduced the concept of different universes, the sequel goes to new lengths to establish the ever-expanding Spider-Verse by actually having its main character, Miles Morales, explore several of these realities.
Source:https://www.cbr.com/spider-man-across-the-spider-verse-all-universes-explained/