[Abstract] Copper is an essential trace element that participates in a variety of metabolic and signaling processes in both oxidized and reduced forms.It is closely related to several aspects of tumor development, and changes in copper homeostasis have a significant impact on processes such as tumor cell growth, metastasis, regulation of the tumor microenvironment, oxidative stress, cell signaling, and the escape of tumor cells from immune surveillance.In tumor cells, copper metabolism promotes immune escape from tumors mainly by regulating the expression of programmed death ligand 1 (programmed Death-Ligand 1，PD-L1).Given the important role of copper in tumor immunity, modulating copper metabolism has emerged as a promising therapeutic strategy.This paper reviews the mechanisms of copper regulation in the human body and explores how disturbances in copper metabolism affect tumorigenesis and progression, as well as the immune and tumor microenvironment.The research value of using copper as a target for tumor immunotherapy is also discussed, providing a theoretical basis for future research directions and clinical applications.