Nvidia GPUs already support AMD's FreeSync monitors, but AMD's GPUs are still not compatible with Nvidia's G-Sync screens. However, Nvidia recently unveiled that these issues are to be eliminated, as 2020 G-Sync screens will provide compatibility for all non-Nvidia GPUs. This is especially beneficial for the upcoming AMD-powered PS5 and Xbox Scarlett consoles.
https://www.notebookcheck.net/PS5-and-Xbox-Scarlett-to-benefit-from-upcoming-Nvidia-G-Sync-support-for-AMD-s-GPUs.444776.0.html
What I am still curious about is, if this means that G-Sync will finally work through HDMI, enabling VRR to finally work between a nvidia card and a freesync monitor through the HDMI port. I know they selected a bunch of freesync monitors to work with their G-Sync via the DP last year. Will this finally just balance it out and make all things compatible?