Linux

Some others have already said the "embrace, extend, extinguish" but here's my take on it. Pair it with Secure Boot and TPM 2.0

• Embrace: Secure Boot can already work with Linux, how lucky! This gives them not exactly control, but authoritative denial over your boot process and hardware.
• Extend: This is the part that remains to be seen. If they feel threatened enough by the shift in the gaming landscape, mind you not over losing out on sales or the hearts of gamers or anything, but again control, they may begin to make Linux offerings. A concession to allow an honest to god, thick Office client on Linux would certainly appeal to some. Adobe gets in on that action to back them up with Photoshop and Activision with Call of Duty, etc.
• Extinguish: TPM 2.0. One of the less talked about features of this is remote attestation ("Remote attestation allows changes to the user's computer to be detected by authorized parties. For example, software companies can identify unauthorized changes to software, including users modifying their software to circumvent commercial digital rights restrictions." - DRM). We're already seeing this with CoD on Windows. They'll allow you to run much requested Windows software on Linux, even provide direct support possibly, but at the cost of not precisely control but authoritative denial. Which still works out to be control in most ways since if you want to use the software and they are to remotely attest, they can also insist that part of that attestation is you running some sort of telemetry or not running software they disagree with.

The reason I think this route is highly likely is because it plays well with uninformed consumers. To the untrained eye it looks like they're giving ground and actually allowing for broader support of their software while effectively gaining control over the environment once again and removing the biggest benefits of running FOSS on your system.