CXCL13 and neoplasm: Boosting of anti-tumour antibody responses by ICB also indicates a broader effect of PD-1/PD-L1-directed immunotherapies on humoral response to self, as well as foreign, antigens, as illustrated by the use of model antigens and in humans where ICB has been reported to boost circulating CXCL13 levels and antibody responses to seasonal influenza vaccination36.