PDCD1 and cancer: Intrinsic PD1 in melanoma cells regulates mTOR signaling and promotes tumor growth.32 Intrinsic PD-L1 is also implicated to be involved in different biological processes, such as autophagy and glucose metabolism.14–16 Here we found that PD-L1 is overexpressed in multiple different cancers including triple negative breast cancer, which portends a poor prognosis (Supplementary information, Fig. S1c).