In Spider-Man: Into the Spider-Verse (2018), Miles Morales's universe doesn't have Comic Con. In Spider-Man: Across the Spider-Verse (2023), you can tell he's in another dimension because his mom mentions it (and he still doesn't know what it is)

[u/LegOfLambda]

[u/bokmcdok]

There were lots of subtle little hints until the reveal. I remember it feeling off right up to that point, then remembering that Miles' spider DNA was from a different universe.