If you bought a VR kit for your Mac and planned on using SteamVR, then you are out of luck. Valve are ending VR support for MacOS, so they can "focus on Windows and Linux". Mackers can still access legacy builds, but this means no more improvements, and no more bug-quashing.
There are ways to jack in without using SteamVR, but still. Ain't that a kick in the teeth.
Here's Valve's little statement. To access the legacy builds you can "opt into a branch by right-clicking on SteamVR in Steam, and selecting Properties... -> Betas." You can also use Boot Camp to load into Windows, but that is a faff and a shame.
SteamVR is Valve's software for running VR games. Not every game needs it, and you can use a tool called OpenComposite to play SteamVR games without having SteamVR installed. I haven't used that myself, so can't speak to how well it works.
Thanks to a surge of interest caused by Half-Life: Alyx, nearly a million Steam users now own cybergoggles - but that's still only 2% of all Steam users, and only 4% of Steam users play on Macs. The number of people with a Mac beefy enough to play VR games will be relatively minuscule, so it's an understandable move, if not a welcome one.
In brighter news, you can at least play Disco Elysium on Mac, thanks to a recent update. Who needs Alyx when you could be an alcoholic detective getting into arguments with your necktie?