Conflict of Interest Disclosures: Ms Fletcher reported receiving funding from Medical Scholars at Vanderbilt University School of Medicine during the conduct of the study. Dr Yeoh reported receiving nonfinancial support from MSD outside the submitted work. Dr Rapisuwon reported receiving personal fees from Replimune and Castle Bioscience and grants from Bristol Myers Squibb outside the submitted work. Dr Mehnert reported receiving personal fees from Merck and Regeneron outside the submitted work. Dr Long reported receiving investigator grants from the National Health and Medical Research Council (NHMRC) and the University of Sydney Medical Foundation during the conduct of the study and personal fees from Agenus, Amgen, Array Biopharma, AstraZeneca, Bayer, BioNTech, Boehringer Ingelheim, BMS, Evaxion Biotech, GI Innovation, Hexal AG, Highlight Therapeutics, Immunocore, Innovent, IO Biotech, Iovance, MSD, Novartis, PHMR Limited, Pierre Fabre, Regeneron, Scancell, and SkylineDX outside the submitted work. Dr Sullivan reported receiving grants from Merck and personal fees from Merck, Pfizer, Novartis, Replimune, and Marengo outside the submitted work. Dr Carlino reported receiving personal fees from Merck Sharpe & Dohme, BMS, Novartis, Amgen, Eisai, Ideaya, Nektar, Oncosec, Pierre-Fabre, QBiotics, Regeneron, Roche, Merck, Sanofi, and Medison outside the submitted work. Dr Menzies reported receiving investigator grants from the NHMRC and Nicholas and Helen Moore during the conduct of the study and personal fees from BMS, MSD, Novartis, Roche, Pierre Fabre, and QBiotics outside the submitted work. Dr Johnson reported holding the Susan and Luke Simons Directorship for Melanoma; receiving grants from the National Cancer Institute, James C. Bradford Melanoma Fund, and the Van Stephenson Melanoma Fund during the conduct of the study; and receiving personal fees from AstraZeneca, BMS, Merck, Novartis, Jackson Laboratories, Teiko, and Pfizer outside the submitted work. No other disclosures were reported.