Al moment Astro Bot 2 (or Astro Bot Rescue Mission 2) has never been announced and there are no real clues as to the existence of a sequel to the famous virtual reality platformer. The robot Astro has become one of the mascots of PSVR and PlayStation 5 (as also demonstrated by Astro's Playroom, a game included in every PS5 and PS5 Digital console), it would therefore not be logical not to think of a new adventure starring this character.
The eventual launch of Astro Bot Rescue Mission 2 could coincide with the debut of PlayStation VR 2 for PS5, unless Sony is planning to produce a "traditional" game rather than a virtual reality platformer. However, these are all hypotheses not supported by real clues, since no announcement has come about. Certainly the will to bet strongly on the ASOBI Team would suggest the need to push the accelerator on the IP Astro Bot, but nothing has been officially confirmed yet.
If you are interested you can download Astro Bot Rescue Mission for free from PlayStation Store as part of the Play at Home initiative along with eight other PS4 and PSVR games such as Abzù, Moss, Subnautica, Enter The Gungeon, Thumper and Rez Infinite.