The incidence of malnutrition is high in patients with malignant tumors while muscle loss is an important feature of malignancy related malnutrition. Inflammation is thought to be a key cause of tumor-associated muscle loss including the involvement of inflammatory factors and immune cells. The activation of inflammatory factors and their mediated signaling pathways leads to the increase of catabolism in muscle tissue. However most drugs targeting inflammatory factors have not shown a good effect on tumor-related muscle loss suggesting that other mechanisms are involved. In recent years it has been found that innate immune cells and adaptive immune cells participate in tumor-related muscle loss through modulating feeding behavior metabolic reprogramming and regulation of muscle tissue stem cells but the specific mechanism has not been clarified. The interaction of immune and metabolic factors jointly leads to muscle loss. The metabolic changes in systemic circulation and the local microenvironment caused by muscle loss also affect the activation and signal transduction of immune cells. Therefore the analysis of the interaction of immune factors with muscle tissue should pay attention to the unity and variability of the systemic circulation and the local microenvironment in order to identify targets on which interventions can be exerted and to provide direction for the treatment of tumor-related muscle loss thereby to improve treatment response as well as clinical benefit in patients with malignant tumor.