CD8A and obesity due to melanocortin 4 receptor deficiency: Ringel et al. (2020) recently showed that blocking CD8 T cells hugely accelerated MC38 tumor growth in vivo. Thus, MC38 cells are more affected by diet-induced systemic changes and suppression of the immune system. Lastly, no effect of an HFD on tumor growth or CD8 T cell function was observed in the CT26 model, suggesting that BALB/c mice are less susceptible to diet-induced changes of the immune system, and BALB/c mice have been reported to be protected from some aspects of obesity (Montgomery et al., 2013).