RecruitingPhase 1Biological interventionNeoadjuvant CADI-05 in Combination With Pembrolizumab for Surgically Resectable Locally Advanced Head and Neck Squamous Cell CarcinomasThe goal of this clinical trial is to learn if drug CADI-05, when used together with pembrolizumab (an FDA approved immunotherapy), can help treat locally advanced head and neck squamous cell carcinoma (LA-HNSCC) in adults. It will also learn about the safety of drug CADI-05. The main questions it aims to answer are: * Does using CADI-05 together with pembrolizumab help the immune system fight cancer better and lead to better results for patients? * What side effects or health problems might happen when people receive these two treatments? Participants will: * Get pembrolizumab by IV (through a vein) once on day 1 of week 1 and again day 1 of week 4. This is standard of care treatment. * Get CADI-05 as a small injection into the skin once a week for 5 weeks. This is the experimental (research) treatment. * Visit the clinic every week for treatments, checkups and tests for 5 weeks. * Have surgery between week 6 and week 7. * Return to the clinic once for a follow-up visit about 30 days after surgery.