F1-F2 to change MBP brightness, CTRL+F1-F2 to change external monitor brightness. Works with my thunderbolt LG 5K. (I dislike the Touch Bar so I always use an e

F1-F2 to change MBP brightness, CTRL+F1-F2 to change external monitor brightness. Works with my thunderbolt LG 5K. (I dislike the Touch Bar so I always use an external keyboard when at my desk)