Inclusion Criteria:

1. The age is 18~75 years old (including the critical value), regardless of gender.

2. Phase II cohort 1, cohort 2: locally advanced squamous cell carcinoma of the head
and neck which only occurred in the oral cavity, oropharynx, hypopharynx and larynx
after histological diagnosis or had no indication of radical local treatment; In the
past, I only received ≤2 line therapy for recurrent and metastatic head and neck
squamous cell carcinoma.

3. Phase II cohort 3, cohort 4, cohort 5: Histologically confirmed nasopharyngeal
carcinoma, stage IVb or recurrent nasopharyngeal carcinoma that is not suitable for
local treatment according to the TNM of AJCC nasopharyngeal carcinoma in the 8th
edition of 2017; In the past, they only received ≤2 line therapy for recurrent and
metastatic nasopharyngeal carcinoma.

4. According to the researcher's judgment, the chemotherapy in this experiment is
applicable.

5. According to the RECIST 1.1 standard, there is at least one measurable lesion (tumor
lesions located in previous radiotherapy areas or other local regional treatment
sites are generally not regarded as measurable lesions, unless the lesions make
clear progress or persist after radiotherapy for three months).

6. The score of physical condition of the ECOG is 0~1.

7. The estimated survival time is ≥3 months.

8. Have sufficient organ functions:

- Blood system (no blood transfusion or hematopoietic stimulating factor
treatment within 14 days): ANC≥1.5×109/L, PLT≥90×109/L, HGB≥ 90 g/L; ② Liver
function: TBIL≤1.5 times the ULN, except Gilbert syndrome; AST and ALT are ≤3.0
times ULN, while subjects with liver metastasis or liver cancer need AST and
ALT≤3.0 times ULN and total bilirubin ≤ 3.0 times ULN;

- Renal function: Cr≤1.5 times ULN; If the creatinine is more than 1.5 times
ULN, the CCR should be ≥ 50 ml/min (calculated according to
Cockcroft-Gault formula);

- Coagulation function: INR≤1.5 times ULN, APTT≤1.5 times ULN, and INR
and APTT≤2.5 times ULN for patients with liver metastasis or liver
cancer.

9. Qualified fertile subjects (male and female) must agree to use reliable
contraceptive methods (hormone or barrier method or abstinence) with their partners
during the trial and at least 6 months after the last medication; The blood
pregnancy test of female subjects of childbearing age must be negative within 7 days
before the first use of the study drug.

10. Subjects must give informed consent to this study before the experiment, and
voluntarily sign a written informed consent form.

Exclusion Criteria:

1. Having received chemotherapy, radiotherapy, biotherapy, endocrine therapy,
immunotherapy and other anti-tumor treatments within 4 weeks before the first use of
the investigating drug, the following drugs should be excluded according to the
following criteria:

① Nitrosourea or mitomycin C was used within 6 weeks before the first use of the
study drug;

② Oral administration of fluorouracil and small molecule targeted drugs 2 weeks
before the first use of the study drug or within 5 half-lives of the drug (whichever
is longer);

③ Chinese patent drugs with anti-tumor indications were used within 2 weeks before
the first use of the study drugs.

2. Received other unlisted clinical research drugs or treatments within 4 weeks before
using the research drugs.

3. The adverse reactions of previous anti-tumor treatments have not recovered to NCI
CTCAE 5.0 grade evaluation ≤1 grade or the relevant provisions of the selection
criteria (except for the toxicity that the researchers judged to have no safety
risk, such as alopecia, grade 2 peripheral neurotoxicity, hypothyroidism stabilized
by hormone replacement therapy, etc.).

4. It is known that it has hypersensitivity to any antibody drugs (NCI CTCAE 5.0 rating
is ≥3), or it has hypersensitivity to research drugs, active ingredients or inactive
excipients of chemotherapy schemes.

5. Have received major surgery (excluding puncture biopsy), major trauma or need to
undergo elective surgery during the trial within 4 weeks before the first use of the
study drug.

6. Having received systemic corticosteroids (prednisone > 10 mg/day or similar drugs
with the same dose) within 14 days before the first use of the study drug, except
for the following cases: using topical, ophthalmic, intra-articular and intranasal
corticosteroids; Short-term use of glucocorticoids for preventive treatment (for
example, prevention of contrast agent allergy).

7. Treatment with other immunosuppressants within 28 days or 5 half-lives (whichever is
longer) before the first use of the study drug.

8. Have used immunomodulatory drugs within 14 days before the first use of the study
drug (Appendix 5).

9. Have been vaccinated with any live vaccine within 4 weeks before the first use of
the study drug.

10. Received allogeneic hematopoietic stem cell transplantation or organ transplantation
in the past.

11. Brain parenchymal metastasis or meningeal metastasis with clinical symptoms.

12. It has active infection and needs intravenous anti-infection treatment at present.

13. Have a history of immunodeficiency disease, including positive detection of HIV
antibody.

14. Active hepatitis B (HBsAg positive and HBV-DNA positive or above the upper limit of
normal value) and active hepatitis C (HCV antibody positive and HCV RNA positive or
above the upper limit of normal value).

15. Having serious and uncontrollable lung diseases (severe infectious pneumonia,
interstitial lung disease, etc.).

16. Have a serious history of cardiovascular and cerebrovascular diseases, including but
not limited to:

① Severe cardiac rhythm or conduction abnormality, such as ventricular arrhythmia
requiring clinical intervention and II-III degree atrioventricular block;

② The mean QT interval (QTcF) corrected by Fridericia method was≥470 ms；

③ Acute coronary syndrome, congestive heart failure, aortic dissection, stroke or
other cardiovascular and cerebrovascular events of grade 3 or above occurred within
6 months before the first administration; (4) There is heart failure or LVEF less
than 50% with the NYHA cardiac function classification ≥II or structural heart
disease with high risk judged by other researchers;

⑤ Clinically uncontrollable hypertension.

17. Suffering from active autoimmune diseases (such as systemic lupus erythematosus,
rheumatoid arthritis, vasculitis, etc.), with the exception of clinically stable
autoimmune thyroiditis, type I diabetes, vitiligo, cured atopic dermatitis in
children, psoriasis that does not require systemic treatment (within the past 2
years), etc.

18. Suffering from other malignant tumors within 5 years before the start of study
administration, except for the following cases: malignant tumors that can be
expected to be cured after treatment (including but not limited to thyroid cancer,
cervical carcinoma in situ, basal or squamous cell skin cancer or breast ductal
carcinoma in situ treated by radical surgery).

19. There is clinically uncontrollable effusion in the third space, which is judged by
the researcher to be unsuitable for the group.

20. Known alcohol or drug dependence.

21. Have mental disorder or poor compliance.

22. Pregnant or lactating women.

23. The researcher thinks that the subject has other serious history of systemic
diseases, or is not suitable to participate in this clinical study for other
reasons.