JAK2 and cancer: In fact, several key regulators of PD-L1 have long been established as cancer-related genes, such as JAK2 (Green et al., 2010; Budczies et al., 2016; Ikeda et al., 2016; Clave et al., 2018), PTEN, MAPK, PI3K, HIF-1α, STAT3 (Marzec et al., 2008; Gowrishankar et al., 2015; Chen et al., 2016), TNFα, NF-κB (Gowrishankar et al., 2015), and INF-γ, etc. Existing small molecular compounds targeting these genes/pathways may be repurposed for modulating PD-L1, thus providing readily tools to improve T cell-dependent anticancer immunity.