Specifically, decreased copper levels downregulate the JAK/STAT signaling pathway, which in turn inhibits IFN-γ-stimulated PD-L1 upregulation as well as by inhibiting EGFR signaling and promoting PD-L1 ubiquitination and degradation, which would enhance infiltration of immune cells CD8+ T cells and NK cells, thereby increasing tumor mouse survival. Here, CD8A is linked to neoplasm.