Several PlayStation games, like Ghost of Tsushima, have separate PS4 and PS5 versions. If you insert a PS4 disc into a standard PlayStation 5, the console will download the digital PS5 version of the game, if available. Otherwise, the PS5 will install the PS4 version of the game. Physical PS4 games can't be upgraded if you have an all-digital PS5. A few games cost less for PS4, like Call of Duty: Vanguard, and will charge you a $10 fee to upgrade to the PS5 version.