New Infamous or Sly Cooper games are not in development
Sucker Punch outright denies the rumours.
It's basically an open secret that Sucker Punch is working on a sequel to Ghost of Tsushima these days, but that hasn't stopped the rumours of a new Infamous and Sly Cooper game of reappearing. Fans of those franchises shouldn't get their hopes up though.
Because Sucker Punch has posted a message where the studio makes it absolutely clear that neither it or any other studio is making or has any plans of making a new Infamous or Sly Cooper. Instead, the closest thing we'll get to anything new from Infamous is that Sucker Punch is working on selling Infamous: Second Son's Cole's Legacy expansion separately on the PS Store...