CD274 and melanoma: These studies suggest that tumor PD-L1 suppresses tumor apoptosis, modulates chemo-resistance through MAPK/ERK activation, controls tumor glucose metabolism and regulates autophagy in ovarian cancer and melanoma.14–16 Interestingly, nuclear staining of PD-L1 is detected in cancer tissues.17 However, the function of nuclear PD-L1 in cancer cells is rarely explored.