KRAS and colorectal cancer: Schell MJ and, Yang Y et al. previously revealed the effect of APC, TP53, and KRAS mutations on the prognosis of colorectal cancer patients (Schell et al., 2016; Yang et al., 2020b), and Cen B et al. further found that mutations in the APC gene could lead to resistance of colonic epithelial cells to CD8+ T cell cytotoxicity by promoting PD-L1 expression, hence driving tumor immune evasion (Cen et al., 2021).