No idea what the project is as yet, but it's in "a new universe".
“Over the past few years, Warner Bros. has shown us first-hand that they understand and respect our creative vision, and we’re looking forward to continuing this relationship,” said IO Interactive CEO, Hakan Abrak.
“IO Interactive has a proud history of creating compelling characters and universes for our players to enjoy—it’s in our DNA. As we embark on this exciting project to create a new universe for IOI together with Warner Bros., we’re currently looking for ambitious talent to join our team in our Copenhagen and Malmö studios for this extraordinary journey.”
Former Hitman publisher Square Enix announced back in May 2017 that it had withdrawn from IO Interactive; the developer took control of the rights to the IP and eventually found it a new home under Warner Bros. It makes sense then that this new project would be developed and published accordingly.
We’ll have more on IO’s new project as information becomes available.