• Voluntarily sign the informed consent and follow the requirements of the protocol;

• Age ≥18 years old;

• Expected survival time ≥3 months;

• Patients with recurrent or metastatic esophageal squamous cell carcinoma confirmed by histology or cytology;

• Consent to provide archival tumor tissue samples or fresh tissue samples of primary or metastatic lesions within 3 years;

• Must have at least one measurable lesion according to RECIST v1.1 definition;

• ECOG 0 or 1;

• Toxicity of previous antineoplastic therapy has returned to ≤ grade 1 defined by NCI-CTCAE v5.0;

• No severe cardiac dysfunction, left ventricular ejection fraction ≥50%;

⁃ No blood transfusion and no use of any cell growth factor drugs were allowed within 14 days before randomization, and the level of organ function had to be adequate;

⁃ Urine protein ≤2+ or \< 1000mg/24h;

⁃ A serum pregnancy test must be performed within 7 days before the start of treatment for premenopausal women who are likely to have children, and the result must be negative and must not be lactating; All enrolled patients should take adequate barrier contraception during the entire treatment cycle and for 6 months after the end of treatment.