IFNG and neoplasm: ICBs are only applicable for MSI-H CRC patients, since MSI-L and MSS CRC patients are unresponsive to ICBs due to the lack of tumor mutational burden, little tumor-infiltrating lymphocytes (TILs), low PD-L1 expression on tumor cells and low IFN-γ expression (Galon et al., 2006; Le et al., 2017; Ganesh et al., 2019).