Anyone running X220 with linux notice some of the blue keys don't work unless youre using certain DEs/WMs (Gnome/KDE work).
For some other WM, 4 keys are only detected by showkey and only in TTY (?)
Using other WM I created udev rules to microphone mute, ThinkVantage, Fn+F8 (trackpad), Fn+Spacebar (zoom)
Some other keys are tricky because xinput does not detect but it can be used in a keybind.
Some others also have internal functionality like Fn+F5 (Wifi) which will toggle wifi with or without a keybind.