https://www.gamespot.com/articles/hearthstone-the-witchwood-expansion-announced-with/1100-6457340/

Blizzard has announced its first Hearthstone expansion for the Year of the Raven, titled The Witchwood. The new expansion will pack 135 cards and a new single-player adventure and it's slated to release in April.

The team debuted six cards today, with more planned reveals coming on March 26 livestream and then steadily leading up to the release. The six shown today give a taste of this expansion's flavor, including two new keywords. The first is Echo, which allows you to play the same card multiple times in the one turn, as long as you have the Mana to pay for it. The second is Rush, which works similar to the existing Charge mechanic but disallows attacks toward the opposing Hero on their opening turn.