OnePlus has announced that its next product launch will be held online. It will indeed take place in April 2020, if not exactly when the rumor mill alleged that it would. The OEM promises "the dawn of a true 5G flagship line up" at this event.
https://www.notebookcheck.net/OnePlus-confirms-an-April-2020-launch-for-the-8-series.459424.0.html