Efficacy and Safety of QL1706 Combined With Nab-paclitaxel and Cisplatin as 1st Line Therapy for Advanced or Metastatic Esophageal Squamous Cell Carcinoma

Inclusion Criteria: * Subjects participate voluntarily and sign informed consent. * 18-75 years, male or female. * Histologically confirmed Unresectable Advanced or metastatic Esophageal Squamous Cell Carcinomas * No previous systemic anti-tumor treatment for unresectable locally advanced or metastatic esophageal squamous cell carcinoma has been received * At least 1 measurable target lesion and/or unmeasurable target lesion according to Response Evaluation in Solid Tumors (RECIST 1.1). * ECOG PS 0-1 * Expected survival ≥ 12 weeks * Adequate organ function (without blood transfusion or growth factors within 14 days prior to first dose), including: ANC ≥ 1.5 × 10⁹/L; Platelets ≥ 100 × 10⁹/L; Hemoglobin ≥ 90 g/L; Serum albumin ≥ 30 g/L; Total bilirubin ≤ 1.5 × ULN; ALT/AST ≤ 2.5 × ULN (≤ 5 × ULN if with liver or bone metastases); ALP ≤ 2.5 × ULN; Serum creatinine ≤ 1.5 × ULN; INR ≤ 1.5 (if not on anticoagulation); * Non-sterilized women of childbearing potential and male participants with such partners must agree to use medically approved contraception during and for 3 months after study drug administration. Women must test negative for serum or urine HCG within 7 days prior to first dose and not be breastfeeding Exclusion Criteria: * Have received anti-PD-1 or anti-PD-L1 antibody therapy; * BMI \< 18.5 kg/m2 or weight loss ≥ 10% within 2 months before screening (at the same time, the effect of a large amount of pleural effusions and ascites on bogy weight should be consider…