Dying Light The Following is free on PS Store. Great DLC and can also be played standalone. : r/PlayStationPlus
Dying Light 2 Stay Human - PS4 & PS5 Games | PlayStation (US)
For anyone worried about cross-gen, you can play with your PS4 friends from PS5 if bought from PS store, as you can see I am currently downloading both versions. Also see file
Dying Light 2 Stay Human: Here's What Comes in Each Edition - IGN