According to the unofficial information yesterday, Blizzard officially announced today Diablo 3 for the switch. Unfortunately, Blizzard has been silent about a release date so far and only gives "this year" as the time frame.
There is a video with game scenes and a first picture of the bonus items for this Diablo III Eternal Collection. There is also an extra homepage for them Switch version.
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Exclusively for Nintendo Switch ™
Discover elements from Zelda's world in Sanctuary. The Eternal Collection for Nintendo Switch ™ includes Cucco as a companion, a Triforce portrait frame and an exclusive transmogrification set with which your heroes can wear Ganondorf's imposing phantom armor. There are also unique decorative wings. (Source: Blizzard)
Here is the message from the Diablo 3 team:
Diablo 3 for the Switch
The minions of Hell have grown incredibly strong since Diablo III was released. Fortunately for the high heavens, reinforcements are already on the way.
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Later this year, Nintendo Switch® players around the world will join forces with the Diablo III: Eternal Collection ™ to use the power of their portable console to destroy demons and claim mountains of loot anytime, anywhere.
Later this year, Nintendo Switch® players around the world will join forces with the Diablo III: Eternal Collection ™ to use the power of their portable console to destroy demons and claim mountains of loot anytime, anywhere.