According to analyst Jean Baptiste Su from Atherton Research, he believes that for 2019, Apple could be seeing the return of Touch ID to the iPhone, the addition of USB-C, and also a smaller notch. These are interesting predictions, although some have pointed out that it does seem rather unlikely and is more of a wishlist than anything.
Apple had previously stated that they had planned to use Face ID all along with the iPhone X and that Touch ID was never an option. To see them return Touch ID to the iPhone would indicate that they might have been wrong about Face ID, although at the same time it is possible that an iPhone with Touch ID could be cheaper.
As for USB-C, we suppose that is only a matter of time given that Apple had already made the switch on the iPad Pro, much to the delight of many users who found it more convenient to add accessories to the tablet that they could not before. In any case take it with a grain of salt for now, but we are still quite a long ways off from hearing anything official.