Valve has announced a new game, but it isn't Half Life 3, nor a brand new property. It's taking a leaf out of both CD Projekt Red and Blizzard's book by introducing a card game based around DotA 2. It's called Artifact and that's about all we really know for now.
We can surmise some sort of elemental facet to the game based on the tri-colors of the game's logo, but that's mere speculation.
Announced during the company's annual The International DotA 2 World Championships, some have pointed out that the disappointment among fans hoping for a Half-Life 3 reveal was palpable.
— nick@TI7 (@nickisnixed) August 9, 2017
As PCGamesN highlights, the nature of the game isn't yet clear. It may be a real world card game, it may be a digital one, probably the latter but perhaps both. We also know it's set to release at some point in 2018, but Valve is being very secretive for now and will no doubt do what it always does: release details as and when the game is ready and not before.