Sony has said in a 2020 corporate report that it plans to bring more first-party games to the PC in the future.
"We will explore expanding our 1st party titles to the PC platform," says the report, "in order to promote further growth in our profitability." The decision to bring more of the Sony in-house catalog to the PC is cited as a key strategic point to the coming direction of its Game & Network services division.
The reason for the change is partially given in the report: "Competition from online PC games and players from other industries is expected to continue to intensify." In short, Sony wants to bring games to the PC because that's where a certain segment of the game-buying audience already is—and presumably because Sony thinks they'll stay there.
The statement comes following the releases of Death Stranding and Horizon Zero Dawn on PC. Both games were PS4 exclusives released much earlier on the console, and per Sony's previous statements that's likely to happen more: Delayed releases on PC of PlayStation console exclusives.
No first party PS5 exclusives have been announced for PC to date, though a several third party exclusives have been. Microsoft has announced both first and third party Xbox Series X exclusives for PC. For more on that, and a list of game titles coming to PC, learn about what the Xbox Series X and PlayStation 5 mean for PC gaming.