Neoadjuvant Sintilimab Combined With Reduction of Cycles of Chemotherapy in Resectable Oral Cavity or Oropharyngeal Squamous Cell Carcinoma (OOC-002)

This study is testing whether adding an immunotherapy drug (sintilimab) to a shorter course of chemotherapy before surgery can help treat mouth or throat cancer. **You may be eligible if...** - You have been diagnosed with squamous cell carcinoma of the mouth or throat (confirmed by biopsy) - You are between 18 and 80 years old - You are in good general health (able to carry out daily activities) - You have not previously received immunotherapy drugs like anti-PD-1 or anti-CTLA-4 treatments - Your blood counts and organ function (liver, kidneys) meet required levels - You are willing to use contraception if you could become pregnant or father a child **You may NOT be eligible if...** - You have had another cancer within the last 5 years - You have an active autoimmune disease requiring steroids - You have active HIV, Hepatitis B or C, or tuberculosis - You are currently pregnant or breastfeeding - You have active lung disease (like pneumonitis) - You are currently taking high-dose steroids or immune-suppressing medications Talk to your doctor to see if this trial is right for you.