The most forwarding smartphone of Samsung in 2018 is the folding one, Samsung Galaxy X. It may go on sales as early as Q3 of 2018. The documents filed in August of 2017 leak that the device has three ways of design.
The first way shows the phone has an internal hinge. The hinge creates a space where the display can fold in and create a semicircle. This semicircle makes for far less stress on the display than it would suffer folding flat. So, the phone will be thicker than Galaxy S and Galaxy Note.
The second shows the folding screen without segmentation, so there is no frame between the two parts of screen. Obviously, it will cost large amount of money. As a result, it has a long way to be used officially.
The third one folds withe a space at its center, something like the Microsoft Surface Book.