This is a single arm, open-label exploratory study conducted in resectable stage II-IIIA NSCLC without EGFR/ALK mutations, aiming to investigate feasibility, safety and efficacy of Sugemalimab in perioperative contexts. Twenty-five resectable stage II-IIIA patients are planned to be enrolled. The proportion of patients with squamous cell carcinoma will not less than 40%. Combined neoadjuvant chemotherapy and immunotherapy with fixed dose of Sugemalimab 1200 mg IV Q3W + Platinum-based chemo in resectable stage II-IIIA NSCLC adult patients followed by surgery. After completion of neoadjuvant therapy (3-4 cycles) and before surgery, a tumor assessment will be done. Patients have to leave the study if there is evidence of progression in neoadjuvant therapy. Pathological response is planned to assessed after surgery. Following surgery, the patients with complete resection will receive an additional 1 year of Sugemalimab q3w. Treatment will commence as soon as clinically feasible post-surgery. Informed consent will be obtained prior to tissue collection and genome sequencing for each participant. Primary tumour tissue will be obtained at diagnosis by biopsy such as percutaneous lung puncture biopsy, bronchoscopic biopsy or endobronchial ultrasound (EBUS) (based on clinical practice). Fresh tumour tissue was collected after surgical resection. Tissues collected were subjected to medically necessary pathology for diagnosis. Specimens were processed for multiplex immunofluorescence, single-cell sequencing and spatial transcriptomics, bulk RNAseq and WES to explore the changes in the immune microenvironment before and after suglizumab administration.