This study is a randomized, double-blind, multicenter, phase III clinical study to compare the clinical efficacy and safety of HLX10 + chemotherapy vs chemotherapy in subjects with locally advanced or metastatic squamous NSCLC who have not previously received systemic treatment.

Eligible subjects in this study will be randomized to Arm A or Arm B at 2:1 ratio as follows:

Arm A (HLX10 arm): HLX10 + chemotherapy (carboplatin nab paclitaxel) Arm B (placebo arm): Placebo + chemotherapy (carboplatin nab paclitaxel) The three stratification factors for randomization include: PD-L1 expression level (Tumor Proportion Scores [TPS]≥50%, 50%>TPS≥1%, TPS<1%), Asian population (yes or no), NSCLC stage (stage IIIB/IIIC or stage IV), and carboplatin AUC (5 or 6).

Inclusion Criteria:

1. Patients with histologically or cytologically confirmed stage IIIB/IIIC and stage IV (AJCC Edition 8) squamous NSCLC where surgery or radiotherapy cannot be performed.
2. No known sensitizing EGFR mutations or ALK, ROS1 gene rearrangements.
3. Major organs are functioning well
4. Participant must keep contraception
5. Patients with prior denosumab use who can agree to switch to bisphosphonate therapy for bone metastases in the study.

Exclusion Criteria:

1. Patients with histologically non-squamous NSCLC. Mixed tumors will be classified according to the primary cell type. Patients do not meet the requirements for enrollment if small cell components and neuroendocrine carcinoma components are present. For non-small cell histology, patients meet the requirements for enrollment if squamous components (e.g., adenosquamous) are present.
2. Patients with known history of severe hypersensitivity to any monoclonal antibody.
3. Patients with known hypersensitivity to any compositions of carboplatin or nab-paclitaxel.
4. Pregnant or breastfeeding females.
5. Patients with a known history of psychotropic drug abuse or drug addiction; or a history of alcohol abuse.
6. Patients who have other factors that could lead to the early termination of this study based on the investigator's judgment.