Introduction Immune checkpoint inhibitors (ICIs) are effective in the treatment of advanced esophageal squamous cell carcinoma (ESCC); however, their efficacy in locally advanced resectable ESCC and the potential predictive biomarkers have limited data. Methods In this study, locally advanced resectable ESCC patients were enrolled and received neoadjuvant toripalimab (240 mg, day 1) plus paclitaxel (135 mg/m2, day 1) and carboplatin (area under the curve 5 mg/mL per min, day 1) in each 3-week cycle for 2 cycles, followed by esophagectomy planned 4-6 weeks after preoperative therapy. The primary endpoints were safety, feasibility, and the major pathological response (MPR) rate; the secondary endpoints were the pathological complete response (pCR) rate, disease-free survival (DFS), and overall survival (OS). Association between molecular signatures/tumor immune microenvironment and treatment response was also explored. Results Twenty resectable ESCC patients were enrolled. Treatment-related adverse events (AEs) occurred in all patients (100%), and 4 patients (22.2%) experienced grade 3 or higher treatment-related AEs. Sixteen patients underwent surgery without treatment-related surgical delay, and the R0 resection rate was 87.5% (14/16). Among the 16 patients, the MPR rate was 43.8% (7/16) and the pCR rate was 18.8% (3/16). The abundance of CD8+ T cells in surgical specimens increased (P = .0093), accompanied by a decreased proportion of M2-type tumor-associated macrophages (P = .036) in responders upon neoadjuvant therapy. Responders were associated with higher baseline gene expression levels of CXCL5 (P = .03) and lower baseline levels of CCL19 (P = .017) and UMODL1 (P = .03). Conclusions The combination of toripalimab plus paclitaxel and carboplatin is safe, feasible, and effective in locally advanced resectable ESCC, indicating its potential as a neoadjuvant treatment for ESCC. Clinical Trial registration NCT04177797

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Esophageal squamous cell carcinoma (ESCC) is one of the most common malignancies worldwide, especially in East Asia. ESCC accounts for more than 90% of esophageal cancer. Currently, neoadjuvant therapy in combination with surgical resection is the mainstay of treatment. However, the overall survival rate of patients with locally advanced ESCC is not satisfactory even when treated following the standard treatment guidelines. With neoadjuvant chemoradiotherapy, chemotherapy, or emerging immunotherapy, continuous exploration of efficacy in relation to ESCC is expected to improve overall survival further. Here, we review and summarize current evidence for efficacy of preoperative therapy for locally advanced ESCC.