Update 17.10.2024: macOS 15 no longer requires root privileges for hidutil, you need to add hidutil and Terminal to 'Input Monitoring' in Settings/Privacy & Security tab.
Update 13.04.2024: On macOS 14.2 hidutil requires root privileges.
If you have a mac with an INT (ISO) keyboard you might want to change the ± key to ~. During my research I found that the information on this topic is not at all centralized. I prefer this option because it does not involve installing new software.
With macOS 10.12 Sierra Apple introduced hidutil as a tool to remap keyboard keys. See TN2450.