You can pre-exhaust muscles so they are too fatigued to contribute significantly to a lift, or you can pre-pump a muscle so that it is primed and ‘feels’ the exercise more.
Example 1: I’m a shoulder dominant presser, if I do a ton of OH pressing prior to bench work, my chest will take over as my shoulders are fatigued.
Example 2: I’m a shoulder dominant presser, if I do some flies to get a good pump in my chest, I’ll feel Incline bench pressing more.
For me, it’s been the extent to which I ‘pre-exhaust’ that contributes to the desired effect.