I’m very dubious about this, but a new rumor from leaker Majin Pu says the iPhone will get a Stage Manager-like user interface feature.
From his post: Source say[s] iPhones with USB-C will support external displays, offering a Stage Manager like interface. While not a full desktop mode, it will allow users to extend their screen space, great for presentations, editing, or enhanced viewing.
Currently, you can connect an iPhone to an external display. But this only allows basic mirroring.
The next versions of iOS, iPadOS, macOS, tvOS, watchOS, and visionOS will almost certainly be previewed at Apple’s upcoming Worldwide Developer Conference. It will be held online (again) from June 9-13.