PDCD1 and oral cavity squamous cell carcinoma: The positive correlation between VISTA, PDL1, and PD1 expressions was in agreement with the literature in non-small cell lung cancer (NSCLC), ENKTCL, HGSOC, breast cancer, gastric cancer, oral squamous cell carcinoma, and epithelioid malignant pleural mesothelioma (5, 8, 17, 30, 32, 38–40).