Sony hasn't had much to say about the next generation of PlayStation, but according to a fresh insider report, first-party game development has already largely shifted to the PS5. This information comes from Niko Partners analyst Daniel Ahmad, who's been an accurate source of insider details in the past.
Per Ahmad, Sony has locked down their releases for the first half of 2019, but the back half of the year is still "in flux." In addition to already-revealed titles, Sony is said to still have a couple unannounced first-party PS4 games from established franchises in the works, although they may be moved to PS5 or released as cross-gen titles. That said, for the most part, Sony's internal development has shifted to the PS5.
As for third-party development, Ahmad confirms that "PS5 dev kits are out there" and he's "heard positive things about [them]," but that we're unlikely to hear more about them any time soon. This mirrors what Digital Foundry's Rich Leadbetter said in a recent video– PS5 dev kits are real, but the console and any concrete information is still a ways off.
https://wccftech.com/playstation-5-sony-main-focus/