sequence vs follow up

I think you probably mean *sequel*, not sequence. That's the most common in any case. There are times when *follow-up* might be used, but they'd be specific and contextual.

For TV shows with episodes, we might just say the next episode. Here's an example: A new season of a show starts, but only has one episode so far. Episode 2 will be released next week. We would not say we're waiting for the sequel or sequence. We would say we're waiting for the next episode. Note: A group of TV shows with episodes is called a season in the US, and is called a series in the UK. (Probably other places too?) That's why I said the word season above. For movies or films, you can say sequel. For example, Avatar 2 was a sequel to the first Avatar movie.

*Sequel,* at least to me, means a movie/show/book that picks up the plot of the previous installment where it left off. If it goes backwards in time, it’s a *prequel.* I would almost never use *sequel* to refer to, e.g. the second episode or season of the same TV show. *Dune 2* is a sequel to *Dune,* just as the book *Dune Messiah* is a sequel to *Dune.* Star Wars episodes I-III* are prequels to *IV-VI.* *Follow-up* is something made by the same person that’s thematically related but has different characters, or *maybe* has the same characters and plot but “feels” separate. Like I could say Luca Guadagnino’s *Queer* is a follow-up to *Call me by your name* because there are similar themes in both and something of an inverted plot, or I might say that the second series of *Fleabag* is a follow-up to the first