Cyber-Leader

The Cyber-Leader was the supreme leader of the Cybermen, depending if the Cyber-Controller is present or not. Cyber-Leaders are sometimes accompanied and assisted by a Cyber-Lieutenant.

Cyber-Leaders were stronger than normal Cybermen. When attacked with gold, they were more resistant (DW: Silver Nemesis). They were designated as the Leader by either a black helmet (DW: Revenge of the Cybermen), or black handle bars on their helmet (DW: Earthshock, DW: The Five Doctors, DW: Attack of the Cybermen and Silver Nemesis).

Cybus Cyber-Leader
The Cybermen from Pete's World did not designate a Leader until they invaded Earth in our universe in 2007. The Cybus Cyber-Leader was identified by black handle bars on its helmet. When the Leader was destroyed, the information it had was downloaded into another Cyberman who would become the new Leader.(DW: Army of Ghosts / Doomsday)