It is a lot easier and more comfortable to play Sekiro using a gamepad than a keyboard and mouse. But for some reason, FromSoftware didn't include the PS4 gamepad button configuration in the PC version of the game.
Currently, the menu includes only Xbox One gamepad prompts.
That's why modders created this little fix. With this mod, you can now play Sekiro using your PS4 controller. You can also remap your button configuration to your liking using this mod.