Why do the conspirators ask Caesar to pardon publius cimber in act III of tragedy Julius Caesar?

In Shakespeare's Julius Caesar, it is Cassius who asks Caesar to pardon Publius Cimber. The conspirators do not seek to pardon Publius Cimber. He is one of the conspirators. Instead, they ask Caesar to overrule the sentence of exile against Metellus Cimber, Publius's brother.