CD274 and neoplasm: However, immune evasion is also facilitated through mechanisms including the downregulation of Major Histocompatibility Complex (MHC) class I molecules and the upregulation of PD-L1 (10).The link between mutational burden and immune evasion is especially evident in areas such as the face and scalp, which are chronically exposed to UV radiation, leading to a higher propensity for local tumor progression.