Using mouse models of prostate and liver cancers, Shalapour and colleagues showed that IL10-producing IgA+ secreting cells are induced in the TME, especially after chemotherapy, by a process requiring TGFβ-receptor signaling in B cells, and can directly suppress cytotoxic CD8+ T lymphocytes in an IL-10 dependent manner [9,10]. The gene discussed is CD79A; the disease is liver cancer.