In a recent interview, OPPO's CEO, Chen Mingyong, stated that the OEM would "strive" to release the first phone with 5G in 2019. This goal would follow on nicely from earlier reports that the company had conducted the world's first video call last year. Otherwise, OPPO plans to release at least one model with the Snapdragon 855 processor in 2019.
https://www.notebookcheck.net/OPPO-is-aiming-for-the-world-first-to-5G-phone-title.402571.0.html