https://www.gamespot.com/articles/wow-makes-welcome-change-to-how-subscriptions-work/1100-6460489/

World of Warcraft's seventh expansion, Battle for Azeroth, is only a few weeks away. In addition to rolling out a big pre-patch that implements new features and sets the stage for the upcoming expansion, Blizzard has now lowered the barrier of entry for players interested in just jumping in to the long-running MMO.

Blizzard has announced that World of Warcraft and all of its current six expansions are now included in the game's monthly subscription fee. Previously, players had to at least purchase the base game and subscribe in order to play, but now they'll get access to all of the game's content through the 2016 Legion expansion simply by paying WoW's $15 per month subscription.