This was just uploaded on the official Miku channel, a new project titled "Hatsune Miku Project G 00" which seems to be happening in Sepetmber of 2020.
Not much more is known... could this be something like that "Unknown 0" (I think it was called) that had to be cancelled, a Miku live event without audience that would be livestreamed? Would fit the current situation (though hopefully Mirai 2020 in Tokyo can still happen - wonder if they will change the theme of the postponed one too since a summer festival doesn't make much sense if not in summer).
Official Web Site : https://pj-g.com/
Official Twitter : https://twitter.com/miku_pjg_00