Tislelizumab , Cyclophosphamide, Mitoxantrone Liposomes, Chidamide, and Prednisone in the Treatment of R/R AITL

Inclusion Criteria: * Pathological diagnosis of AITL according to WHO classification in 2016, and pathological diagnosis of AITL according to WHO classification in 2016, and at least one evaluable or measurable lesion meeting Lugano2014 criteria: lymph node lesion, detectable lymph node length\>1.5cm; non-lymph node lesion, detectable extra-nodal lesion length\>1.0cm; * Refractory or relapsed after at least one systemic therapy (including chemotherapy, stem cell transplantation)\*; * Age ≥18 years old, male or female, ECOGPS≤3 points; * Life expectancy exceeds 3 months; * Follow-up conditions. Patients understand the characteristics of the disease and voluntarily join the study protocol for treatment and follow-up. * : Relapse: patients achieve complete response (CR) or partial response (PR), disease progression (PD) ≥6 months; refractory: treatment failure (no PR) or PD \<6 months after the last chemotherapy. Exclusion Criteria: Subjects who meet any of the following criteria are not eligible for inclusion in this study: * Patients with abnormal liver and kidney function, specifically serum direct bilirubin, serum indirect bilirubin and/or alanine aminotransferase, aspartate aminotransferase and serum creatinine\>2 times normal values, unless abnormal liver and kidney function is considered to be related to lymphoma; * Bone marrow failure, specifically defined as absolute neutrophil count (ANC)\<1.5\*10\^9/L or platelets \<75\*10\^9/L or Hb\<90g/L, unless changes in h…