After killing who knows how many henchmen and taking out the lieutenants and capos of New Bordeaux, it’s time to end Mafia III, and that means going after Sal and Giorgi Marcano. It’s not quite an open and shut case, though, as it turns out that there are two endings you can choose from. Spoilers for Mafia III at this point, obviously.
You’re going to start this ending by heading to the construction site of the Casino where Sal and Giorgi are holed up. Take out the men leading you to Giorgi, the same way you always do. Once you head up to Giorgi’s office, shoot him and the men protecting him, then walk over to his bleeding form. Watch the cutscene wherein Giorgi finally gets his, and Lincoln will steal his elevator key to head up to where dear old dad is sitting. There are no enemies here, so all you have to do is walk up the stairs and let the cutscene play out. Once it ends, hit the interact button (X on the Xbox One, Square on the PS4), and you’ll put an end to his rein. Head back to the elevator, hit the button, and another cutscene will play out. You’ll meet Leo Galante from Mafia II, and he’ll let you rule New Bordeaux, with the caveat of giving 20% of his earnings to the Commission, as Sal had done. Lincoln agrees, but there’s still the matter of what to do next.
Ending I: Leave Town
This one is pretty simple. All you have to do is drive your car to the predetermined point at the edge of the city. Once you hit the final arrow, the game will take over from there, and Lincoln will have left New Bordeaux for good. Whichever Underboss is still alive will take control of the city while Lincoln lives a life of solitude. Occasionally, he’ll send a letter to Father James from wherever he’s living at in the moment, but otherwise he keeps to himself.