Inclusion Criteria:

1. Histological or cytological examination confirmed recurrence or metastasis of
nasopharyngeal carcinoma;

2. Patients who have not previously received systemic treatment for recurrent or
metastatic diseases (For patients who have previously received induction
chemotherapy, adjuvant chemotherapy or concurrent chemoradiotherapy, patients who
relapsed at least 6 months after the cessation of chemotherapy can be enrolled).

3. Age: 18-75 years old, male or female;

4. Perfomance Status: 0~1;

5. At least one measurable lesion (according to RECIST v1.1, long diameter of
measurable lesion scanned by spiral CT should be ≥ 10 mm or short diameter of
swollen lymph node should be ≥ 15 mm; according to RECIST vl.1 standards, a
previously treated lesion with local treatment can be used as target lesions after
clear progress);

6. Blood routine examination: 1) Hemoglobin (HB)≥ 90g / L; 2) Neutrophil count (ANC) ≥
1.5 × 109 / L; 3) platelets (PLT) ≥ 80 × 109 / L;

7. Liver function: 1) Serum total bilirubin (BIL) ≤ 1.5 times the upper limit of normal
(ULN); 2) alanine aminotransferase (ALT), aspartate aminotransferase (AST])< 2.5 ×
ULN; if liver metastasis, ALT and AST ≤ 5 × ULN; Renal function: Albumin ≥ 28g / L
；Serum creatinine (Cr) ≤ 1.5 × ULN，or creatinine clearance rate ≥ 60 ml / min ;

8. Coagulation function : APTT and international normalized ratio (INR)< 1.5 × UNL;

9. Patients of childbearing age agree to take appropriate contraceptive measures. Serum
pregnancy test was negative in women of childbearing age within 2 weeks before
enrollment.

10. Patients agree to provide pathological tissue specimens (wax blocks or paraffin
tissue sections 5-10 pieces) ;

11. Expected survival ≥ 3 months;

12. Patients volunteered to participate in this study and signed informed consent;

Exclusion Criteria:

1. Patients with local recurrence and suitable for surgery or radiotherapy;

2. Patients with a known history of severe allergies to monoclonal antibody therapy;

3. Patients who had previously received PD-1 monoclonal antibody or PD-L1 monoclonal
antibody or CTLA4 monoclonal antibody;

4. Clinical significance of heart disease, including severe cardiac insufficiency : New
York Heart Association (NYHA) cardiac insufficiency grade IV, unstable angina, acute
myocardial infarction within 6 months before screening, congestive heart failure,
Q-Tc interval greater than 500ms;

5. Patients with autoimmune diseases requiring treatment, or patients with a history of
systemic use of steroids / immunosuppressive agents, such as : hypophysitis,
pneumonia, colitis, hepatitis, nephritis, hyperthyroidism, hypothyroidism;

6. Other serious and uncontrollable concomitant diseases that may affect the compliance
of the program or interfere with the interpretation of the results, including
uncontrolled diabetes, or lung diseases (interstitial pneumonia, obstructive
pulmonary disease, and symptomatic bronchial spasm) ;

7. Known hepatitis B (HBV) (HBsAg positive and HBV-DNA ≥ 103IU / ml), hepatitis C (
HCV) infection (HCV antibody positive and HCV-RNA measurable) ; and other subjects
with acquired and congenital immunodeficiency diseases, including, but not limited
to, those infected with HIV;

8. Severe active infection;

9. Symptomatic patients with central nervous system metastasis;

10. Patients with a history of other malignant tumors (unless those who have been cured
for more than 5 years);

11. Have a serious history of neurological or psychiatric disorders, including dementia
or epilepsy;

12. Drug abuse, medical, psychological or social conditions that may interfere with the
participant 's participation in the study or the evaluation of the study results;

13. Researchers believe that patients who are not suitable for enrollment.