Some miRNAs can act as tumor suppressors by targeting immune checkpoint molecules, such as PD-L1, PD-1, CTLA-4, and TIM-3, in tumor cells, such as ovarian cancer, prostate cancer (PC), and non-small cell lung carcinoma (NSCLC) or immune cells, such as T cells and DCs in the TIME (8). The gene discussed is PDCD1; the disease is neoplasm.