Cancer cells can activate PD-L1 expression through various oncogenic signaling pathways, such as phosphoinositide 3-kinase/protein kinase B (PI3K/PKB)37, extracellular-signal-regulated kinases/mitogen-activated protein kinase (Erk/MAPK)38, anaplastic lymphoma kinase/signal transducers and activators of transcription 3 (ALK/STAT3)39, Janus kinase (JAK)/STAT40, and myeloid differentiation primary response gene 88/tumor necrosis factor receptor associated factor 6 (MYD88/TRAF6)41 or in response to inflammatory cytokines that are produced by the infiltration of immune cells, such as IFNs42,.43 Here, STAT3 is linked to cancer.