It's a Unity game though, It might just run like garbage in the first place. Not to say all Unity games run like crap, but a lot of them do. If it's especially slowing down during scoping, it could mean the texturestreaming is not working properly. Given the fact you have both a GTX 1080 with 8GB of VRAM and 16GB of system ram, it shouldn't really be struggling in terms of texturestreaming.
If it was the CPU exclusively, it should just have low FPS in general. @gear69 It depends a little on how poorly the game runs at scoping. Does it stutter heavily and afterwards recover, or does the framerate just flatout drop and not recover?
EDIT: I'm reading the game has been suffering from memory leaks after a certain patch or update. That might also explain if it was stuttering.