Department of Head and Neck Surgery, University of Texas MD Anderson Cancer Centre, Houston, TX, USA. Electronic address: ngross@mdanderson.org. Department of Medicine, Division of Hematology/Oncology, and Department of Dermatology, Massachusetts General Hospital, Boston, MA, USA. Department of Cutaneous Oncology, Moffitt Cancer Centre, Tampa, FL, USA. Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, USA. Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA. Bloomberg-Kimmel Institute for Cancer Immunotherapy and Sidney Kimmel Comprehensive Cancer Centre at Johns Hopkins, Baltimore, MD, USA. Department of Dermatology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany; Skin Cancer Center, University Cancer Centre Dresden and National Center for Tumor Diseases, Dresden, Germany. Head and Neck Medical Oncology, Nebraska Cancer Specialists, Omaha, NE, USA. Rogel Comprehensive Cancer Centre, University of Michigan, Ann Arbor, MI, USA. Levine Cancer Institute, Atrium Health, Charlotte, NC, USA. Department of Hematology and Medical Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA. Department of Dermatology, Schleswig-Holstein University Hospital, Kiel, Germany. Duke Cancer Institute, Durham, NC, USA. Department of Cancer Care Services, Royal Brisbane and Women's Hospital and University of Queensland, Brisbane, QLD, Australia. Department of Dermatology, University Hospital of Essen and German Cancer Consortium, Partner Site Essen, Essen, Germany. Departments of Dermatology, Medicine, and Oncology, George Washington University School of Medicine and Health Sciences, Washington, DC, USA. Harold C Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA. Department of Dermatology, Johns Hopkins Hospital, Baltimore, MD, USA. Department of Medical Oncology, Peter MacCallum Cancer Centre and University of Melbourne, Melbourne, VIC, Australia. Department of Thoracic and Head and Neck Medical Oncology, University of Texas MD Anderson Cancer Centre, Houston, TX, USA. Regeneron Pharmaceuticals, Tarrytown, NY, USA.