Sintilimab and Decitabine for Patients With Relapsed/Refractory or Advanced NK/T-cell Lymphoma

Inclusion Criteria: Histopathology and immunohistochemistry confirmed diagnosis of NK/Tcell lymphoma according to WHO 2016 criteria. * refractory or relapsed after initial remission, or stage III-IV de novo patients * PET/CT or CT/MRI with at least one objectively evaluable lesion. * General status ECOG score 0-3 points. * The laboratory test within 1 week before enrollment meets the following conditions: Blood routine: Hb\>80g/L, PLT\>50×10e9/L. Liver function: ALT, AST, TBIL ≤2 times the upper limit of normal. Renal function: Cr is normal. Cardiac function: LVEF≥50%, ECG does not suggest any acute myocardial infarction, arrhythmia or atrioventricular conduction above I Blocking. * Sign the informed consent form Exclusion Criteria: Active infection requires ICU treatment. Concomitant HIV infection or active infection with HBV, HCV. Patients who are infected with HBV but not active hepatitis at the same time are notexcluded. Significant organ dysfunction Pregnant and lactating women. Had a history of autoimmune diseases, and disease was active in the last 6 months. Those who were known to be allergic to drugs in the study regimen. Patients with other tumors who require surgery or chemotherapy within 6 months. • Other experimental drugs are being used.