The administration of first-line pembrolizumab monotherapy or combined chemotherapy has been shown to improve survival among patients with recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC). However, over 80% of the patients still experience disease progression within a year. Upon progression, treatment options are notably constrained, typically comprising methotrexate, docetaxel, and cetuximab. The median progression-free survivaland overall survival following chemotherapy, targeted therapy, or their combination are dismally low, ranging from 2-3 months and 6-8 months, respectively. The clinical trials CheckMate 141 and KEYNOTE 040 have led to the approval of Nivolumab and Pembrolizumab as second-line treatments for R/M HNSCC. Nevertheless, the response rates to immune monotherapy are limited, ranging from 10% to 35%. Even after receiving standard second-line immunotherapy, over 80% of patients encounter disease progression within 6 months, and more than 60% succumb to the disease within a year. Therefore, there is a dearth of a standardized treatment for R/M HNSCC after the failure of first- or second-line PD-1 (L1) inhibitors and/or platinum-based therapy