They observed the following findings: (1) The T cell population exhibited a complex diversity based on their surface with high expression of PD-1, LAG, 3, TIM-3, and IDO in some T cell subgroups; (2) Treg proportions in the tumor lesions were significantly increased across all patients; (3) PD-1+, TIM-3+, or LAG-3+ T cells are recognized as exhausted subsets, and (4) the proportions of exhausted CD4+ and CD8+ T cells were distinctly higher at the tumor sites. This evidence concerns the gene IDO1 and neoplasm.