Rumors have been running wild for a while that Sly Cooper 5 and/or a new Infamous games were on the way, but today Sucker Punch Productions decided to put an end to it. On their site, they published a post titled, "Upcoming inFAMOUS 2 UGC Maintenance and Legacy Franchises" which addressed the situation surrounding their franchises.
Opening up they state that both franchises are near and dear to their hearts, but that the team needs all its people working on its current project due to the increasing scope and complexity of games. They explain that no one is working on projects in these franchises either at Sucker Punch or other studios. Here's how they put it:
As our games continue to grow in scale and complexity, they require the full attention of our studio. With our focus on our current project, we have no plans to revisit inFAMOUS or Sly Cooper right now, and no other studio is currently working on projects related to those franchises either. These characters are very special and near and dear to our hearts, so while we’d never say never to re-opening those doors down the road, for now there are no inFAMOUS or Sly Cooper games in development.
That makes it pretty clear there is no Sly Cooper 5, or new Infamous game, while also ruling out remaster projects by the nature of their use of the project instead of a new game. It's not all bad news as they state that they are going to be doing maintenance on Infamous 2 UGC servers to move them to a new home and keep them up longer as they want to keep them alive as long as possible, although they do raise the specter of shutting them down in the future. Additionally, they are working to put the Cole's Legacy DLC for Infamous Second Son on the Playstation store for more people to be able to try. Previously the DLC had only been available to those who bought the collector's edition of the game.
This should hopefully put to bed rumors that had been going around about Sly Cooper, and Infamous, which had previously pinpointed a possible September reveal for both titles. It's also a reminder that even reliable sources of rumors can be wrong. In the meantime, you can probably look forward to more of the samurai simulator series that started with Ghost of Tsushima.