I have yet to see a foldable phone that was usable and made any kind of sense. I guess if Apple does one thing well, it's over-engineer the user experience so if they bother then it will probably be decent but horribly expensive. At least Apple has some semblance of a tablet market to bring to bear too. Not sure why the heck Samsung and etc were farting around with foldable phones.
Regardless I don't think it will go beyond prototype, foldable phones are too expensive, have too many design compromises and offer few benefits.
Playing: Xenoblade Chronicles DE, Ys IX, God of War
Watching: Lupin, You me and the Apocalypse, Days of Thunder