Blizzard has announcd that Diablo Immortal will be available for download on Android and iOS devices on June 2. The game is coming to PC, too, with the open beta starting at the same time. Pre-registrations are live on Blizzard's website.
https://www.notebookcheck.net/Diablo-Immortal-mobile-launch-date-set-for-June-2-PC-open-beta-to-commence-on-the-same-day.615469.0.html