Valve has announced a new game and it's a spin-off of DOTA called Artifact: The Dota Card Game, and it's unsurprisingly about cards. Aren't you GLaDOS?
The announcement was made in front of DOTA and Valve fans during The International 2017 DOTA tournament. To say the crowd's reaction was plunged into despair would be an understatement as it almost appeared as if Valve was about ready to make a sequel reveal.
Half-Life 3, Left 4 Dead 3, Portal 3 - there's a thing for 3's right now with the studio which hasn't done much in the way of setting trends for a while, but instead has followed the trends set by others. Artifact: The Dota Card Game is likely to be on the receiving end of fan ire over Valve's perpetual silence.
Artifact: The Dota Card Game releases in 2018 for unspecified platforms, but expect PC at least.