CD4 and neoplasm: As the memory resting CD4 T cells were likely to have been induced by the MHC-II-carrying tumor cells in subgroup 3 (Table 1), and could be reactivated to cytotoxic CD4 T cells through contact with tumor cells possessing the corresponding epitopes (MacLeod et al., 2010), potential ICB responders could be found in this subgroup of never-smoker patients with LUAD.