CD274 and mismatch repair cancer syndrome 1: There are many factors that are involved in the efficacy of immune checkpoint inhibitors treatments, including infiltration of cytotoxic T cells (Van Allen et al., 2015), neoantigen load and mutation frequency (Snyder et al., 2014), serum PD-L1 levels (Nishino et al., 2017), and mismatch repair deficiency (Le et al., 2015).