"we don’t have any plans specific to Xbox consoles in virtual reality or mixed reality." - Mike Nichols (Microsoft’s chief marketing officer of gaming)
Skipping VR this gen and saving it for next gen makes sense logically. MS already said that the standard Xbox One and Xbox One S are too weak to do VR properly, so any headset would only work with Xbox One X, and there simply isn't a big enough install base of XB1 X owners to justify R&D costs and VR exclusive development budgets for a headset that is limited to just XB1 X owners. Better to save it for next gen when the headset will be open to the much larger Xbox Scarlett install base.