According to Korean publication ETNews, Samsung is aiming to supply Apple with its latest Y-OCTA OLED panels for Apple's 2019 iPhones. Y-OCTA (or Youm On-Cell Touch AMOLED) is Samsung's term for its on-cell touch flexible AMOLED technology.
Y-OCTA panels are thinner than Samsung's previous flexible Add-On Touch panels as the touch sensor is deposited directly on the encapsulation (TFE) layer. The optical features are also better as the touch layer is below the polarizer and enables the use of a non-ITO grid, there's no need for a support film (see image above) and the number of layers is lower.
Samsung estimates that Y-OCTA also cuts production costs by around 30%, but apparently it is still struggling with lower production volumes for Y-OCTA displays, and so ETNews estimates that Samsung may not be able to supply Apple with Y-OCTA panels for all of its 2019 iPhone models, it will probably only be adopted in the highest-end version.