Toripalimab in Combination With Standard Treatment for Human Papillomavirus (HPV) Positive Throat Cancer

This study tests whether adding an immunotherapy drug (toripalimab) to standard chemoradiation therapy improves outcomes for people with HPV16-positive throat cancer (specifically oropharyngeal squamous cell carcinoma) that has spread to nearby lymph nodes or involves larger tumors. **You may be eligible if...** - You have been diagnosed with HPV16-positive squamous cell cancer of the throat (oropharynx) - Your cancer is at an advanced stage (spread to lymph nodes or involves a large primary tumor) - You are at least 18 years old - You have at least one measurable tumor - You are in good enough health to undergo chemoradiation **You may NOT be eligible if...** - Your cancer has spread to distant organs - You have serious immune system problems or autoimmune disease - You have had prior treatment that would prevent you from safely receiving the study treatment Talk to your doctor to see if this trial is right for you.