Has there ever been a movie that was a secret sequel to another movie?

I was wondering if there has ever been a movie that was actually a sequel/prequel to another movie without it being known or marketed that way.

So for example director X made a film and then they later made another film that was not marketed or talked about in connection to that first film in any way and just seen as a separate thing that ended up being connected to the first film whether that be throughout the movie itself or a twist ending sort of thing.

Submitted August 20, 2023 at 12:41AM by FutureRecipe7 https://ift.tt/DVFeb8P