The relationship between a cathode and an anode involves

The relationship between a cathode and an anode involves the transfer of electric charge between them. The cathode is the negative terminal on the battery, which has zero electric potential. The anode is the positive terminal on the battery and has the battery's maximum electric potential. Current flows from the battery's anode (positive terminal) to the cathode (negative terminal). In electron flow, electrons leave the negative side of the battery and move towards the positive side of the battery.

Hence, The relationship between a cathode and an anode involves Electrons.