A central finding in our study is that B cell subclasses IgG1 and IgG3 play a critical role in anti-tumor response to neoadjuvant chemoimmunotherapy, and IL-21 (mainly secreted by Tfh cells) is the driving force to induce B cell isotype switching to IgG1 and IgG3, not IgA in tumor lesion. Here, CD79A is linked to neoplasm.