Inclusion Criteria:  Histologically confirmed Recurrent/Metastatic Nasopharyngeal Carcinoma Subjects failure after platinum-based chemotherapy and anti-PD-1/PD-L1 antibody therapy; Able and willing to provide signed informed consent form, and able to comply with all procedures. Life expectancy >= 12 weeks as judged by the Investigator. Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1 at trial entry. Disease must be measurable with at least 1 uni dimensional measurable lesion by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Adequate hematological, hepatic and renal function as defined in the protocol Other protocol-defined inclusion criteria could apply  Exclusion Criteria:  Anticancer treatment within 28 days before the first dose of study drug. Major surgery within 28 days before start of trial treatment. Systemic therapy with immunosuppressive agents within 7 days prior to the first dose of study drug; or use any investigational drug within 28 days before the start of trial treatment. With any active autoimmune disease or history of autoimmune disease. With active central nervous system (CNS) metastases causing clinical symptoms or requiring therapeutic intervention. History of immunodeficiency including seropositive for human immunodeficiency virus (HIV), or other acquired or congenital immunedeficient disease, or any active systemic viral infection requiring therapy. Previous malignant disease (other than the target malignancy to be investigated in the trial) within the last 2 years. Subjects with history of cervical carcinoma in situ, superficial or non-invasive bladder cancer or basal cell or squamous cell cancer in situ previously treated with curative intent are NOT excluded.