I found an easy level up cheat for Sniper Elite 4. I'm using the PS4 version but I guess it'll work for PC and xboxone also.
This is what I do.
At the end of the level it automatically saves for you. Well for me it did.
I load up that automatic savegame and I take a few steps and the level ends.
It says I've gained some XP.
Instead of continuing I load up that exact same savegame again.
Oh look, I've gained XP again.
repeat. Oh look I've leveled up.
Enjoy.
This is what I do.
At the end of the level it automatically saves for you. Well for me it did.
I load up that automatic savegame and I take a few steps and the level ends.
It says I've gained some XP.
Instead of continuing I load up that exact same savegame again.
Oh look, I've gained XP again.
repeat. Oh look I've leveled up.
Enjoy.