Research is being conducted on the association of programmed cell death ligand 1 (PD-L1) with various types of cancer, including oral squamous cell carcinoma, gastric cancer, and non-small cell lung cancer. The studies examine the relationship between PD-L1 expression and clinical outcomes, such as metastasis and prognosis. The findings appear to vary across different cancer types, with some studies suggesting a correlation between PD-L1 expression and patient outcomes, while others investigate the predictive value of PD-L1 in different contexts.