CD4 and neoplasm: First, we found that compared to that of patients with LUAD or LUSC with wild-type KEAP1, LUAD or LUSC patients with KEAP1 mutation had a suppressed tumour immune microenvironment, including a decreased density of a suite of CD8+ and CD4+ T lymphocytes, macrophages, and B lymphocytes, which was observed not only in LUAD but also in LUSC patients.