In gene level, tumor cells can activate PD-L1 expression of via multiple oncogenic signaling pathways involving IFN-γ/JAK2/IFN [24], PI3K [36], ALK/STAT3 [37], MEK/ERK/STAT1 [38], MYD88/TRAF6 [38] or exposure to inflammatory cytokines such as IFN-γ [39] produced by infiltrating immune cells. Here, IFNG is linked to neoplasm.