The Cisco Kid is a fictional character found in numerous film, radio, television and comic book series based on the fictional Western character created by O. Henry in his 1907 short story "The Caballero's Way", published in the collection Heart of the West. In movies and television, the Kid was depicted as a heroic Mexican caballero, even though he was originally a cruel outlaw.
The Cisco Kid came to radio October 2, 1942, with Jackson Beck in the title role and Louis Sorin as Pancho. With Vicki Vola and Bryna Raeburn in supporting roles and Michael Rye announcing, this series continued on Mutual until 1945. It was followed by another Mutual series in 1946, starring Jack Mather and Harry Lang, who continued to head the cast in the syndicated radio series of more than 600 episodes from 1947 to 1956.
The radio episodes ended with one or the other of them making a corny joke about the adventure they had just completed. They would laugh, saying, "'oh, Pancho!" "'oh, Ceeesco!", before galloping off, while laughing. (Source: wikipedia.org)