How can I remove keyboard shortcut on my iMac Pro?

I think you mean holding down the Control key and pressing the left mouse button acts as a right click.

I am not aware of any way to change this.

This has been standard on the mac for decades. Traditionally, Apple mice only have one button.

Even the current trackpads and mice, while they can be made to do right clicks, do not have physically separate buttons.

Thus control-left click has been set as the way to emulate a right click - as far back as the Classic Mac OS, in the previous century :-)

I don't think it is possible to disable this functionality, but maybe there is some obscure command to turn this off.

What would you expect or want to happen with Control-left click instead? Just the same as a left click? Or something else? And, if you don't mind my curiosity, why?

ctrl + lmb

What is lmb?

Not every shortcut can be removed or edited but those that can may be found in System Preferences -> Keyboard -> Keyboard Shortcuts