The importance of sIgA in our preclinical proof of concept for apyrase function in ICB was demonstrated by (i) the percentage of ileal sIgA-coated bacteria negatively correlated with the tumor size of mice treated with anti–PD-L1 independently of the addition of apyrase; (ii) the adjuvant activity of apyrase during ICB was lost in mice lacking IgA. This evidence concerns the gene CD79A and neoplasm.