https://www.pcgamer.com/steam-link-anywhere-stream-from-home/

Valve has announced the pre-GDC launch of two potentially major new features for Steam: The "early beta" release of Steam Link Anywhere, which will enable streamed gaming to any compatible device, and Steam Networking Sockets APIs, granting developers access to the technology and infrastructure that underlies CS:GO and Dota 2. 

Steam Link Anywhere is an extension of Steam Link that will enable users to connect to their PCs and play games from anywhere (thus the name), rather than being limited to a local network. It's compatible with both the Steam Link hardware and app, and will be rolled out automatically (and freely) to everyone who owns the hardware with beta firmware installed, the Android app beta, or the Raspberry Pi app. You'll also need to be enrolled in the Steam client beta, and have the latest version installed.