CD4 and neoplasm: The priming of CD4+ and CD8+ T cells helps signals to cytotoxic T lymphocytes and further establishes efficient and durable anti-tumor immunity.33 34 CD56+ cells are a major cell subset of NK cells, which provide protection against infectious pathogens and cancer.35 Our findings suggest that neoadjuvant PD-1 blockade might enhance the systemic priming of antitumor T cells and natural killer cells in the ESCC microenvironment.