Interestingly, CAR T cells were no longer detectable by flow cytometry at day+20 after axi-cel infusion in one of the responding patients, but we observed a new expansion of CD4+ and CD8+ CAR T cells after one dose of nivolumab (at day 144 after CAR T-cell infusion). Chimeric antigen receptor-engineered (CAR) T cells have demonstrated their efficacy in relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL), but still fail to induce a durable complete remission (CR) for most patients.[[1]] One potential mechanism of immune escape is the exhaustion of CAR T cells induced by the immunosuppressive tumour microenvironment.[[3]] The PD1/PD-L1 immune checkpoint pathway is strongly associated with CAR T-cell exhaustion.[5] The use of anti-PD1 inhibitor could generate a new CAR T-cell expansion and may improve the response.[6] We here report on 11 patients with R/R DLBCL who did not achieve CR after CD19 directed CAR T-cell therapy by axicabtagene ciloleucel (axi-cel) and who were treated subsequently with anti-PD1 nivolumab (240 mg/m SP 2 sp every 2 weeks) between 2019 and 2020. Safety and efficacy of nivolumab in patients who failed to achieve a complete remission after CD19-directed CAR T-cell therapy in diffuse large B cell lymphoma. [Extracted from the article]