No, Commodus did not die in the arena. He was assassinated in his palace in 192 AD.
Commodus, the Roman Emperor known for his love of gladiatorial combat, did participate in many contests in the arena, claiming victory in numerous bouts. However, his demise came from a conspiracy against him rather than a fatal encounter during a gladiatorial competition.
His death was orchestrated by his own advisors and a wrestling coach named Narcissus, who was hired to carry out the assassination. Commodus was strangled in his bath as part of a plot to end his tyrannical rule. Despite his flair for the dramatic and his self-portrayal as a gladiator, his end was far removed from the arena.