CD Projekt RED revealed their plans for "two massive expansions" in the works for The Witcher 3: Wild Hunt. These expansions are called Hearts of Stone and Blood and Wine, both of which offer up about 30 combined hours of gameplay.
Hearts of StoneBlood and Wine, a 20-hour-plus tale that will introduce the all-new in-game region of Toussaint, will take Geralt to a land untainted by war, where an atmosphere of carefree indulgence and knightly ritual masks an ancient, bloody secret.

Hearts of Stone will be released in October. Blood and Wine is slated for release in the first quarter of 2016. From the looks of the Steam page for the Expansion Pass, it will run you $24.99 (USD) to get both of these expansions.