In principle, it makes perfect sense for game studios to start work on the next stage after the release of a single game, but it is always good to confirm this. In the case of ZA/UM, the studio behind Disco Elysium, this is done through a vacancy.
ZA/UM is a fairly young developer (started in 2016) who released Disco Elysium three years ago. Then a “final cut” of the beloved RPG was made, but no more than that. Time for something new? Apparently yes, because there are three open vacancies: Environmental concept artist, leading environmental artist and sales specialist. In addition, the lead environment artist states that Unreal Engine 5 is used. This immediately sets high expectations for those “environments” that these artists need. Furthermore, the potential new game appears to have nothing to do with Disco Elysium and to do with science fiction and outer space. It’s even described in a very particular way as one of the job openings, because the studio is looking for someone who “realizes that there are more things between heaven and earth than they are philosophical about.” In addition, experience with procedural content is required, which means that the development is done using algorithms and that the game may be different each time, thanks to the algorithms. It looks like something is really in development, right?