Our previous study, a single-center, prospective, single-arm Phase II study (Keypoint001) has demonstrated the efficacy and safety of neoadjuvant chemotherapy combined with immunotherapy in locally advanced (cT3-4N+M0) esophageal squamous cell carcinoma. The results show that the pathological complete response rate (pCR) reaches 35%, and the major pathological response rate is over 70%, which is much higher than that of patients receiving chemotherapy alone. Meanwhile, no severe adverse drug reactions have been found in terms of safety, so this treatment regimen is safe and reliable. However, the cycle of neoadjuvant immunotherapy is still under exploration. Currently, the mainstream research centers adopt a regimen of 2 to 4 cycles. The exploration results of our center have found that most patients' conditions can be further alleviated after 4 cycles compared with after 2 cycles, but there are still a small number of patients with no obvious remission. Therefore, we consider observing whether patients with no obvious remission can achieve a better pathological response rate through further radiotherapy.