This question might be better (at least on my side of the Atlantic) asked the other way round: "In which sport is the Commissioner's Trophy awarded?"
Trouble is, Wikipedia tells us that there was another trophy with the same name, which was awarded to the Coach of the Year in the International [Ice] Hockey League between 1985 and 2001.
So if you do ask it the other way round, you should probably either find a way of eliminating the ice hockey trophy in the question, or allow "Ice hockey" as a correct answer.
As an example of the former workaround: "The Commissioner's Trophy is awarded to the team that wins the most prestigious annual competition, in which sport?"
© Haydn Thompson 2020