A Study Comparing Two Immunotherapy Options for Human Papillomavirus Positive HPV-Positive Head and Neck Cancer After Treatment

The goal of this clinical trial is to learn if the combination of cemiplimab and fianlimab can improve outcomes compared to cemiplimab alone in adults with Human Papillomavirus Positive HPV-positive head and neck cancer who have detectable minimal-residual disease after definitive treatment. The main question(s) it aims to answer are: * Does combining cemiplimab with fianlimab provide better results in preventing cancer recurrence than cemiplimab alone? * Is the combination treatment safe and well-tolerated by patients? Researchers will compare the group receiving cemiplimab alone to the group receiving the combination of cemiplimab and fianlimab to see if the combination leads to improved treatment outcomes, such as better disease control and longer survival. Participants will: * Receive either cemiplimab alone or a combination of cemiplimab and fianlimab. * Attend regular follow-up visits for monitoring of treatment efficacy and side effects. * Undergo assessments to measure disease progression and response to treatment.