Sequels, remakes, remasters, and spin-offs are all possibilities for these IPs.
Shadow of the Tomb Raider

Embracer Group is already looking forward to "sequels, remakes, remasters, and spin-offs" for their newly obtained IPs. In early May, Embracer Group acquired Eidos-Montreal, Crystal Dynamics, Square Enix Montreal, and several former Square Enix IPs such as Deus Ex and Tomb Raider.

This week, Embracer shared their latest financial results (PDF), during which they say that they are looking to produce those sequels, remakes, etc. for these IPs. They are also looking into the possibility of "transmedia projects" for the new IPs, which would include things like television shows, movies, or just about any other form of media outside of video games.

Embracer Group does own Dark Horse Comics and the board game company Asmodee. These two properties could be utilized to "enable the use of gaming IPs across yet another media."

The last mainline Tomb Raider title was the 2018 release of Shadow of the Tomb Raider. We already know that Crystal Dynamics started work on a new Tomb Raider prior to this acquisition. That new game will be built on Unreal Engine 5.

Deus Ex hasn't had a new game since 2016 when Deus Ex: Mankind Divided was first released. Likewise, Thief has not had a new entry since 2014. All of these franchises, and several more, are just ripe for a new entry. With Embracer Group, the possibility of this happening is far greater than if they stayed with Square Enix.