My guess: Bloodborne 2.
In other news, Layden confirmed to Time that Sony’s E3 2017 pres conference this year will follow the same format as last year, being less of a press conference and more of a software showcase. “The crowd will only have to suffer I think in aggregate 90 seconds of me,” he joked. “And in the middle will be all the games.”
Great article on everything from how well the PS4 Pro and PSVR are selling, to Horizon's big numbers and their digital sales, but this is the section that refers to E3:
Alongside God of War Layden confirmed that we'll also see Naughty Dog's Uncharted: The Lost Legacy, Insomniac's Spider-Man, Days Gone from Sony's Bend Studio, and Polyphony's Gran Turismo Sport. Sadly, we couldn't get a rise out of him on what InFamous and Sly Cooper developer Sucker Punch is working on, or whether there'll be any word of Sony partnering with FromSoftware on Bloodborne 2. "You can ask," he quipped – but wouldn't say anything further. We may get another glimpse of Hideo Kojima's Death Stranding, though. "We're partnering with him and financing development of Death Stranding. His team has taken the Decima engine that Guerrilla built for Horizon Zero Dawn and they're using that as the base for Death Stranding. Both teams are working from a joint code base now and building on it. It's kind of like a holy grail in game development. Some studios outside of my world have invoked that kind of discipline – "thou shalt all use this engine" – but we've sort of left it to our studios to find the engine they need within the technologies that we have available."
Sony will also be pushing its partnerships, "We have a Call of Duty partnership, a Destiny 2 partnership, Red Dead partnership with Take-Two and Star Wars with EA," says Ryan. While unwilling to specify the nature of these deals, it's likely we'll see trailer premieres at the very least.