PDCD1LG2 and esophageal squamous cell carcinoma: However, some PD-L1-positive patients of esophageal cancer did not benefit from such therapies, while some patients lack of PD-L1 still showed clinical response [10, 12], implying that other molecular interacts with PD-1 such as PD-L2 may be important for immunotherapy efficacy in ESCC.