Innate resistance refers to the constitutive expression of PD-L1 in tumor cells due to amplification of the PDL1 gene or aberrant activation of oncogenic signaling pathways [48,49,50,51,52]; adaptive resistance to immunity refers to the expression of PD-L1 in tumors or immune cells in response to inflammatory factors that are secreted in the TME during antitumor immune responses, and IFN-γ is one of the main cytokines that is responsible for inducing the adaptive expression of PD-L1 [53]. Here, IFNG is linked to neoplasm.