It's probably DOTA Auto Chess.
DOTA Auto Chess

Valve was given a new trademark this week. This trademark is for an upcoming "computer game" called DOTA Underlords. Literally nothing else is known about this title. There is speculation that it may be the name of Valve's standalone release of DOTA Auto Chess, but that's as much of a guess as anything else.

For all we know, it could be a VR title, something to do with Artifact, or something completely unexpected.