Clinical Study of XPO1 Inhibitor Selinexor Combined With COPL in Newly Diagnosed Advanced NK/T-cell Lymphoma

Inclusion Criteria: * Age≥14 years, male or female; * Pathologically confirmed newly diagnosed NK/T cell lymphoma according to WHO classification criteria 2016; * At least one measurable lesion, defined as bidimensionally measurable, intranodal lesion \> 1.5 cm in short axis and extranodal lesion \> 1.0 cm in short axis; * ECOG score 0\~2; * Clinical stage III\~IV; * Normal major organ function, meeting the following definitions: Hematology: WBC ≥ 3.5 x 10 9/L, PLT ≥ 75 x 10 9/L, Hb ≥ 80 g/L; Liver and kidney function: AST and ALT ≤ 3.0 ULN; TBIL ≤ 2.0 mg/dL; CCr ≥ 60 mL/min; liver and kidney function impairment caused by tumor compression is not limited by this; Fibrinogen: normal at first cycle * Expected survival \> 6 months * Agree to use effective contraception; * Understand and voluntarily sign written informed consent Exclusion Criteria: * Prior allogeneic HCT (allo-HCT) * Active autoimmune disease * Primary central nervous system lymphoma; * Patients with infection which requiring treatment. Could be re-enrollment after infection control; * Known history of human immunodeficiency virus (HIV) infection * Known hypersensitivity to the study drug or any of its excipients; * Presence of other active malignancy requiring treatment that could interfere with this study; * Patients with other conditions not suitable for enrollment as judged by the investigator.