It is highly unlikely that this trainer will be updated.
Mafia II no longer exists in the Steam store.
Everyone who bought Mafia II from Steam got a free upgrade to the definitive edition of the game. Use the Definitive Edition trainer.
This is all explained in the recent posts just above yours - please read forums before posting in them.
Definitive Edition trainer: Mafia II (Definitive Edition) Cheats and Trainer for Steam.