The highly anticipated foldable phone from Samsung might include a slide-out display system, which would provide a wider screen suitable for movie-watching, streaming and playing games, especially when the 5G networks go online. This could add to the overall thickness of the device, but the benefits easily outweigh the downsides.
https://www.notebookcheck.net/Samsung-is-patenting-slide-out-displays-for-future-phablets.290482.0.html