IFN-γ has several mechanisms through which it can regulate PD-L1 expression, dependent on the type of tumor; in most cases it involves JAK-STAT-related pathways and the PI3K/Akt pathway, while the MEK/ERK and NF-Kβ signaling pathways are also known to be implicated in some tumors [97,98,99,100,101,102]. This evidence concerns the gene IFNG and neoplasm.