TIME, tumor immune microenvironment environment; EGFR, epidermal growth factor receptor; TKIs, tyrosine kinase inhibitors; ADC, adenocarcinoma; MDSC, myeloid-derived suppressor cell; NK, natural killer; NKT, natural killer T; IDO, indoleamine 2, 3-dioxygenase; DC, dendritic cell; MHC, major histocompatibility complex; IFN-γ, interferon-gamma; TNF-α, tumor necrosis factor alpha; PFN, perforin; GzmB, Granzyme B; NSCLC, non-small cell lung cancer. Here, IDO1 is linked to non-small cell lung carcinoma.