PDCD1 and cancer: This may be consistent with preclinical mouse studies that identified that PD-1+ T follicular helper cells interact with PD-L1 in B cells to support plasma cell formation and in the absence of either PD-1 or PD-L1, the development of long-lived plasma cells was decreased.36 37 Depleting B cells from solid tumors in preclinical models has shown minimal impact on CPI treatment efficacy in certain cancers,38 which may highlight an opportunity to perform prophylactic B cell depletion in patients with high risk for irAEs mediated by B cells in at least some tumor types.