The FTC lawsuit has put Microsoft under the harshest antitrust scrutiny in the US in more than two decades. It also could be a crucial test for the FTC at a time when it’s trying to rein in the tech industry broadly, with mixed success.

In its initial challenge to the merger in its in-house court last year, the FTC alleged the deal would harm competition by turning Microsoft into the world’s third-largest video game publisher — allowing it to raise video game prices with impunity, restrict Activision titles from rival platforms and harm game quality and player experiences on consoles and gaming services.