There are still a lot of time prior to Samsung releases the Galaxy Z Flip follower, however that does not imply that development hasn’t begun currently. In fact, according to a design patent at WIPO (World Copyright Office), Samsung is checking out 2 possible styles both of that include a triple-camera module on the back.
The Model A features a familiar design with horizontal camera positioning, however due to the larger module, the secondary screen utilized for alerts looks a bit smaller sized. Whereas Model B embraces a vertical stack providing much more space for the tiny OLED screen, which grows in size as a result.
The patent itself does not expose anything else and it does not guarantee that Samsung would use either of those styles. It does hint at the possibility of Samsung working on a design that embraces triple cameras on the back and it would make sense provided that a lot of flagships provide at least three focal lengths.
Source (in Dutch)