Abstract: As a common tumor of digestive system, esophageal cancer (EC) is histologically classified as either esophageal squamous cell carcinoma (ESCC) or esophageal adenocarcinoma (EAC). Although conventional treatment modalities for EC include surgery, chemotherapy, and radiation, not all patients respond to initial systemic treatments, with a significant proportion of patients experiencing disease recurrence after the initial treatment. Immune checkpoint inhibitors can enhance antitumor adaptive immunity by rejuvenating antitumor immune responses, thereby improving clinical outcomes. In particular, immune checkpoint inhibitors for programmed cell death-1 (PD-1) have emerged as an important treatment modality for several cancer types, with the number of clinical research on PD-1 checkpoint inhibitors for EC constantly increasing. However, despite the good preliminary clinical results of the KEYNOTE-181 and ATTRACTION-03 trials, there is an urgent need to increase awareness regarding the full scope of EC-related immunology background. Only then can we develop more effective immunotherapeutic strategies and accurately select patients who may benefit from PD-1 checkpoint inhibitors.