It says both, but it includes everything you need in the box to play all of the included cases... So what it says, and what the truth is, are two different things.
Will the cases be new or will there be repeats ?
They're all new if you have only played the SHCD base game, but I believe some of the cases in this new game are revamps of older released cases (expansions for the Sleuth edition, I guess).
If you jumped on board with the Ystari box like I did, then you won't get repeats.