A recent Bloomberg article revealed many interesting details about what's going on with PlayStation's studios.
According to journalist Jason Schreier, Visual Arts Service Group was working in a remake for the original The Last of Us. This team, founded by Michael Mumbauer, always helped Sony finish many of their big titles.
The production, which began while Part II was being developed, had issues. For example, Sony didn't give the small team a budget to hire more people. Furthermore, when Naughty Dog finished Part II, Sony decided to put many of ND's devs behind Visual Art Service Group's project. By the end, many of Mumbauer's employees abandoned the project, including himself. "Deflated, the small group’s leadership has largely disbanded, according to interviews with eight people familiar with the operation," added the journalist.
Bend Studio experienced another rough situation. When the studio pitched a sequel to Days Gone, it was rejected. "Although the first game had been profitable, its development had been lengthy and critical reception was mixed, so a Days Gone 2 wasn’t seen as a viable option," wrote Schreier.
But it doesn't end there. Bend was assigned to help Naughty Dog with a new online experience and, apparently, a new Uncharted. However, the team wans't feeling comfortable with the decision: they "feared they might be absorbed into Naughty Dog". Fortunately, it seems they could step out of the project and now they are working on a new title of their own.
For further details, please check Bloomberg's article.