Immune checkpoint inhibitors enable T cells to kill tumors by reversing the combination of programmed cell death protein-1 (PD-1) of T cells and programmed cell death-Ligand 1(PD-L1) of tumor cells which is aimed at patients with recurrent EOC characterized by microsatellite instability-high, mismatch repair deficiency, or high tumor mutation burden [8]. The gene discussed is PDCD1; the disease is neoplasm.