HAVCR2 and head and neck squamous cell carcinoma: Tregs can express and upregulate co-inhibitory receptors, making them more immune-suppressive.72 Tim-3+ Tregs have been also shown to be induced by 10 Gy+anti-PD-L1 in an orthotopic mouse tumor model of head and neck squamous cell carcinoma (HNSCC) and to be the cause of treatment resistance73 and described as highly immune-suppressive in patients with HNSCC.74