According to reports, Samsung is already prototyping the Galaxy Z Fold4 and Galaxy Z Flip4, its next-generation foldable smartphones. Big changes could be afoot for both devices, such as a built-in S Pen for the Galaxy Z Fold and an under-panel camera in next year's Galaxy Z Flip.
https://www.notebookcheck.net/First-next-generation-Samsung-Galaxy-Z-Fold-and-Galaxy-Z-Flip-details-emerge.579965.0.html