CD38 and neoplasm: A recent study indicates that the overexpression of CD38 on T cells after PD-1/PD-L1 blockade may contribute to acquired resistance by suppressing CD8+ T cell proliferation and inducing their differentiation into exhaustive CD8+ T cells, and the combination of CD38 and PD-L1 blockade substantially reduces primary tumor burden and metastasis compared with PD-L1 blockade alone in vivo.