Can Steam restore a game that was revoked by the publisher?

In most cases, no. Steam will not restore a game revoked due to a third-party key issue and does not issue refunds for third-party purchases. The only exception is if the revocation was a publisher mistake — in rare cases, developers have worked with Valve to restore keys and have notified affected buyers through the game's Steam community page. If you believe the revocation was an error, check the game's Steam community page for developer announcements, and contact the seller for a replacement key or refund.