Publisher FuRyu has filed a logo trademark for Caligula 2. Series producer Takuya Yamanaka teased the existence of a sequel to The Caligula Effect in June of last year, so it could very well be that an announcement is forthcoming.
The original Caligula Effect was a Vita-exclusive RPG with talent from the Persona series behind it. A remake titled The Caligula Effect: Overdose came out in 2019. Neither of these editions were particularly well-received, but there are definitely interesting concepts in this series rife for further exploration!
Keep an eye on RPGFan for more coverage of Caligula 2.