In several tumors, such as ovarian, melanoma, NSCLC, and gastrointestinal cancers, PD-1 was usually co-expressed with LAG-3, TIM-3, TIGIT, and VISTA on TILs In ovarian cancer, the number of PD-1+LAG-3+CD8+T-cells expressing TNF-α and IFN-γ were significantly decreased, compared to their equivalents without the co-inhibitory receptors [173,174,175,176]. Here, PDCD1 is linked to ovarian cancer.