There's always at least one simple feature that gets too complicated with each new console generation. Transferring saves may be the main suspect this time around, especially when it comes to sending save data from PS4 to PS5. Even with all the mind-boggling controversies about it, it can still be easily understood with a little breakdown.
Can PS4 save data be transferred to PS5?
Since the PS5 is backwards compatible with digital titles and PS4 discs, users can use their old saves when playing PS4 games on the console. However, that doesn't mean you can transfer old saves to PS5 remasters of PS4 titles. For example, Marvel's Spider-Man for PS4 can be played on PS5 with your old files intact. However, the exclusive remastered version for PS5 will not play these saves.
Moving your save data can be done in three ways. The easiest method is provided for PS Plus users as they can access their downloaded PS5 saves from the online storage system. It can also be transferred either by an external USB storage drive or by linking the two consoles via a WiFi Transfer Process.
Will saves work on games that are on both PS4 and PS5?
A pattern is becoming increasingly clear that most offline PS4 save data will not play on PS5 game iterations. A good indicator of this is that Mortal Kombat 11, Madden 21, and NBA 2K21 will not carry over specific mode progression offline. If you want to continue playing these saves, then you will need to play the PS4 versions of these titles on PS5, as they are technically different games.
Most developers, such as those in the titles above, will provide cross-progression support for online saves. This mostly seems possible because most of the inline components are part of an outside service. An example of this is Call of Duty which requires players to log into an Activision account on Multiplayer and Warzone, which ultimately ties your online saves to the account rather than just one platform.
Finally, be aware that some PS4 titles won't work with PS5, but don't worry; the list of excluded is incredibly short.