Until now the only way to run a high-end VR system on a Mac was by booting into Windows, but that didn't solve the fact that Apple had yet to offer a GPU option that was actually good enough for VR. The next best thing was to plug in your desired NVIDIA card via an external enclosure like the Razer Core, but you'd still be stuck with Windows. Thankfully, Apple has finally decided to take matters into its own hands by adding VR graphics support to the upcoming macOS High Sierra due this fall, and it's also offering a Thunderbolt 3 external GPU dev kit as of today at WWDC.
Source: Apple