Altogether, reduced CD8+ T-cell infiltration—caused by PCSK9-mediated deficiency of the tumor antigen peptide–MHC that could be targets for cytotoxic T-cell recognition—might be one of the reasons why patients with PCSK9lo tumor tissue were more likely to benefit from ICIs compared with those with PCSK9hi tumor under advanced NSCLC treatment. Here, PCSK9 is linked to neoplasm.