Bandai Namco just revealed during their SAO livestream that a Persona 5 Royal and Sword Art Online will have a collaboration, specifically on two SAO games – Sword Art Online: Memory Defrag and Sword Art Online: Integral Factor.
— 【公式】SAO メモリー・デフラグ (@saomd_gameinfo) January 13, 2020
Here’s a short clip of their teaser (courtesy of Nmia):
Sword Art Online: Memory Defrag and Sword Art Online: Integral Factor are both available now for iOS and Android, while Persona 5 Royal is available now for the PlayStation 4 but for Japan consumers at the moment. An English release is set for March 3.
For more info you can check out their official website.