RecruitingPhase 1Biological interventionSafety and Efficacy Study of Anti-PD1 Armored CD19 CAR-T Cells in Adult Subjects With Relapsed or Refractory Diffuse Large B-cell LymphomaThe purpose of this study is to investigate the safety and tolerability of anti-PD1 armored CD19 CAR-T Cells in adult subjects with relapsed or refractory diffuse large B-cell lymphoma.