ASUS Function Keys
If you're here, you probably have an ASUS laptop that has special function keys, and/or a backlit keyboard that you might want to enable in macOS. This functionality can be enabled, but it requires a VirtualSMC Plugin called AsusSMC. This plugin and associated daemon can manage your keyboard backlight and all of the special keys on your keyboard. Setting it up can be complex, and may be different across different models. Rather than try and explain it all, here's a link to the project which provides all of the documentation that you should need.