https://arstechnica.com/gadgets/2024/07/report-apple-begins-serious-work-on-a-foldable-iphone/

https://www.macrumors.com/guide/foldable-iphone/ seems like it's in the works

A 2027 version of the question

@Nikos A commenter there also linked this article saying that they are working on it. https://www.theinformation.com/articles/apple-develops-a-foldable-clamshell-iphone

Does it have to have a folding screen, or does any folding component qualify?

@JimHays Hmm. I assumed it would be a folding screen (since current and previous iPhones have all essentially been large touchscreens), but good question!

Considering that others have already traded on this market, let's say that any folding hardware component that's part of the core structure of the device qualifies.