Hearthstone's next expansion will be announced later this month

Blizzard will announce Hearthstone’s next expansion later this month, according to game director Ben Brode. 

Here's everything we know so far about the Year of the Raven, Hearthstone's coming year of content.

Brode had already said the next expansion would be revealed in March, but in case that went under your radar, he dropped the news again in a light-hearted Twitter exchange with a fellow Blizzard designer. 

from
https://www.pcgamesn.com/hearthstone/hearthstone-next-expansion-release-date