IL21 and neoplasm: To verify whether the level of IL-21 in peripheral blood plasma can reflect the changes in the local tumor microenvironment and whether it is related to the clinical response of neoadjuvant pembrolizumab and chemotherapy, we checked the concentration of plasma IL-21 by ELISA collected from 17 treatment-naive patients and 13 neoadjuvant pembrolizumab and chemotherapy patients in our validation cohort.