Financial Support: This work was support by a research grant of the Hiege foundation against skin cancer, Hamburg, Germany and was also funded in part through the NIH/NCI Cancer Center Support Grant P30 CA008748. BW reports grants from Merck/MSD, during the conduct of the study; grants and personal fees from Bristol Myers Squibb, personal fees from Philogen, personal fees from Roche, outside the submitted work; JCH reports personal fees from BMS, MSD, Roche, GSK/Novartis, Amgen, outside the submitted work; CaB reports personal fees from AstraZeneca, personal fees from Amgen, personal fees from BMS, personal fees from Roche, personal fees from GSK, personal fees from MSD, personal fees from Novartis, outside the submitted work; MAP reports grants from Bristol-Myers Squibb, personal fees from Bristol-Myers Squibb, outside the submitted work; BS reports other from MSD, outside the submitted work; KK reports personal fees from MSD, personal fees from BMS, during the conduct of the study; LH reports other from MSD, other from BMS, other from GSK, other from Roche, outside the submitted work; and speakers fees from MSD; RG reports grants from Novartis, Pfizer, Roche, Johnson & Johnson, personal fees from Roche, BMS, GSK, Novartis, MerckSerono, MSD, Almirall, Amgen, Galderma, Janssen, Boehringer Ingelheim, Pfizer, personal fees from Roche, BMS, MSD, LEO, GSK, Amgen, Novartis, Almirall, personal fees from Roche; BMS, MSD, outside the submitted work; AB reports personal fees from pharmaceutic industry, outside the submitted work; ChG reports other from BMS, other from GSK, other from Novartis, outside the submitted work; MM reports grants and personal fees from BMS, grants and personal fees from Roche, personal fees from GSK, grants and personal fees from MedImmune, outside the submitted work; CB reports personal fees from MSD, personal fees from BMS, personal fees from GSK, personal fees from Roche, grants and personal fees from Novartis, outside the submitted work; DS reports personal fees from Amgen, GSK, BMS, Novartis, Roche, Amgen, Merck, outside the submitted work; RD reports grants from Novartis, grants and personal fees from Bristol-Myers Squibb, grants and personal fees from Roche, grants and personal fees from GlaxoSmithKline, personal fees from Merck Sharp & Dhome, personal fees from Amgen, outside the submitted work; PAA reports grants and personal fees from Bristol Myers Squibb, grants and personal fees from Roche-Genentech, personal fees from Merck Sharp & Dohme, grants and personal fees from Ventana, personal fees from GSK, personal fees from Novartis, personal fees from Amgen, outside the submitted work; GH reports personal fees and non-financial support from MSD, personal fees and non-financial support from BMS, personal fees and non-financial support from Roche, outside the submitted work; CG reports grants and personal fees from Merck, during the conduct of the study; personal fees from Amgen, grants and personal fees from BMS, personal fees from Novartis, grants and personal fees from Roche, grants and personal fees from GSK, outside the submitted work; JW reports grants from Bristol Myers Squibb, grants from Merck, during the conduct of the study; grants and other from Bristol Myers Squibb, grants and other from Merck, outside the submitted work.