you likely got a free chapter of hitman 1 2016 back when it was episodic and unfinished. the file size of the original releases of Hitman 1 and 2 are extremely bloated and no longer supported so I highly recommend ignoring anything that isn't DLC/Access Passes for World of Assassination (originally Hitman 3 which will make DLC labelling even more confusing).
The one on sale is the vanilla Hitman 1 missions.
HITMAN 3 Access Pass: HITMAN 2 Expansion will get you the vanilla missions from the second game.
Hitman World of Assassination standard includes vanilla Hitman 1, 2 and 3 missions + the new roguelite game mode.
WoA Deluxe edition has all the DLC bonuses and missions for all three games.
https://i.imgur.com/Iv5fRLt.gif