PDCD1 and cancer: Several additional blocking abs targeting multiple Gal-9 axis binding partners, including TIM-3, CEACAM1, or PD-1 are also being examined in multiple advanced cancer types, including melanoma, Merkel cell, brain, cervical, colon, esophageal, gastric, liver, lung, and pancreatic cancer, as well as leukemia and lymphoma (Table 1).