Valve's Artifact: Everything We Know So Far

It’s not Half-Life 3, Portal 3, or anything else ending with ‘3’, but yesterday Valve announced its first full game since releasing Dota 2 in 2013, called Artifact. Maybe not what people were expecting, Artifact is a Dota-themed card game revealed with the teaser trailer below.
Details are sparse, but here’s everything we know about Artifact so far:
A Dota-themed digital trading card game developed by Valve. From the sound of it, Artifact aims to recreate a game of Dota 2