This page is a guide on if you should kill or leave McKay in Far Cry 6.
Play through the main story of Far Cry 6 until you reach the operation “The Deported”, then eventually you’ll find yourself face to face with McKay and you’ll be given a choice to either kill or just leave him alone.
This choice doesn’t affect anything in terms of the story, but it will change your reward. Killing Mckay will reward you with the Wrist Gear “Canadian, Eh?” which rewards you with extra Pesos upon killing enemies with poison. Other then this you’ll get a different bit of dialogue from Yelena at the end of the Operation.
Leaving McKay will give you 5000 Pesos at the end of the operation. Regardless of your choice here McKay will not be making any more appearances in the story. Alternatively, if you’d like to acquire the 5000 Pesos while still punishing McKay slightly, then you can shoot him once in the leg.