• Able to provide written informed consent and can understand and agree to comply with the requirements of the study and the schedule of assessments.

• Male or female, aged ≥ 18 years.

• Histologically confirmed diagnosis of esophageal squamous cell carcinoma.

• Dose escalation and dose expansion stages: After at least one line of systemic treatment (PD-1 antibody combined with platinum-based chemotherapy) has progressed or is intolerable. The following situations are regarded as the failure of the first-line standard treatment:

‣ Tumor recurrence/progression during neoadjuvant/adjuvant immunotherapy combined with platinum-containing chemotherapy.

⁃ Patients with disease recurrence within 6 months after completing neoadjuvant/adjuvant treatment, and this neoadjuvant/adjuvant treatment is also defined as first-line treatment.

• Dose escalation and dose expansion stages :At least one measurable lesion by RECIST v1.1, that is, the long diameter of non-lymph node lesions shown by CT or MRI is ≥10 mm or the short diameter of lymph node lesions is ≥15 mm. If the CT scan slice thickness is \>5 mm, the minimum diameter of the lesion is twice the slice thickness (acceptable examination results within 28 days before signing the ICF).

• Neoadjuvant treatment cohort: Have not received any anti-tumor treatment for esophageal cancer, including radiotherapy, chemotherapy, surgery, etc.; and plan to receive surgical treatment after the completion of neoadjuvant treatment.

• Eastern Cooperative Oncology Group (ECOG) performance status score: 0 or 1.

• The expected survival period is ≥12 weeks.

• The HLA typing is HLA\*A: 0201 and/or HLA\*A: 1101.

⁃ The organ function level in the screening period must meet the following requirements (no blood transfusion or blood products, no use of hematopoietic stimulating factors and other drugs to correct the number of blood cells before the examination):

∙ Absolute neutrophil count (ANC) ≥ 1.5 × 109/L;

‣ Platelet count (PLT) ≥ 100 × 109/L;

‣ Hemoglobin (Hb) ≥ 90 g/L;

‣ Total bilirubin (TBIL) ≤ 1.5 × ULN;

‣ Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 2.5 × ULN, ≤ 5 × ULN for those with liver metastasis;

‣ Serum creatinine (Cr) ≤ 1.5 × ULN, or creatinine clearance rate (Cockcroft-Gault formula) ≥ 45 mL/min;

‣ International normalized ratio (INR), prothrombin time (PT) ≤ 1.5 × ULN;

‣ QTc interval calculated according to the Fridericia standard, ≤ 450 ms for men and ≤ 470 ms for women;

‣ Urine routine/24-hour urine protein quantification: Urine protein qualitative ≤ 1+ (if urine protein qualitative ≥ 2+, then 24-hour urine protein \< 1 g can be enrolled);

‣ Cardiac function: Left ventricular ejection fraction ≥ 50%.

⁃ Eligible patients (male or female) with fertility must agree to adopt a medically approved physical contraceptive measure (such as an intrauterine device, condom, tubal or vas deferens ligation, etc.) during the trial and within 6 months after the last administration; Serum or urine HCG tests of women of childbearing age must be negative in the screening period.