Luna was announced along with many of their other device updates at the event. Sources indicate that Amazon has been developing Luna for quite some time now. Luna will go in direct competition with the other cloud gaming services like Stadia, GeForce Now, xCloud, and Playstation Now.
The service is available now, with a catch – you have to Request Early Access. For more info: https://www.cloudgamingbattle.com/amazon-announces-luna-their-premier-cloud-gaming-service/