Valve said last month that Half-Life: Alyx will not be delayed beyond March: Valve announced today that the VR prequel to Half-Life 2 will be released on March 23.

The Steam page still says March 2020, but that's the official Valve Twitter feed, so we can be sure; Valve also released three supposedly new screens.

And those who purchase the Valve Index VR rig will begin receiving pre-order bonuses the week of March 2: a Steam VR Home environment inspired by the Alyx location; availability of the Index and related hardware (which is still out of stock overall) More details regarding availability will be announced "shortly."