With Twitch Prime, people got a free subscription to Twitch, the Amazon-owned livestreaming site, with free games from small studios and unique, in-game equipment and discounts for larger titles like Grand Theft Auto and League of Legends. Prime Gaming will expand those benefits and offer more titles and content, but will no longer require a Twitch account for access.
Source: After a Flop, Amazon Makes Another Foray Into Video Games