Inductive sensors use a magnetic field to detect objects.  Capacitive sensors use an electric field.  In order to be sensed by an inductive sensor an object must be conductive. This limits suitable targets to metal objects (for the most part). In order to be sensed by a capacitive sensor the target doesn’t need to be conductive. A capacitive sensor will react to an object acting as a dielectric material as well as a conductive object. This makes metal and non-metal objects suitable targets.