The term 'All-Star Duo' refers to two people who have achieved great success in their respective fields. The crossword solution for this term is 'GEMINI, ' which is a reference to the astrological sign of the same name. GEMINI is associated with duality, which is fitting for a duo. People born under the sign of GEMINI are known for their intelligence, wit, and adaptability, which can be seen in many successful duos.