If you mean current:
sudo apt update
will alert you to pending available package updates through out all of your repositories and if there are any, you can run
sudo apt upgrade
Or all in one go:
sudo apt update && sudo apt full-upgrade
If you want to check history of what available packages have been released (independent of what is on your system)...
New or experienced, this is actually not as straight forward as it should be.
If we look over at Windows OS, it is even less so.
This is not due to developers wanting to keep secrets, but to low demand on the users part for this. I mean... a lot of users ignore all updates...
Above, I used ls -l /var/lib/apt/lists | grep noble-security for Zorin OS 18 in terminal. That is one way you can do it.