PDCD1 and head and neck squamous cell carcinoma: Future studies will employ immunocompetent C57BL/6 mice with 4NQO-induced primary HNSCC models, combined with immune checkpoint inhibitors (e.g., PD-1/PD-L1 inhibitor Pembrolizumab [35], CTLA-4 inhibitor Ipilimumab [38]), to explore synergistic antitumor effects of PLS3 targeting and immunotherapy, providing preclinical evidence for clinical translation.