PDCD1LG2 and colorectal carcinoma: Interestingly, Wang et al. demonstrated that PD-L2 was expressed in approximately 40% colorectal cancer (CRCs), however, PD-L1 expression in only 12% patients, and it was PD-L2 but not PD-L1 expression independently associated with poor survival of CRC patients, further suggesting the special role of PD-L2 in tumor immunity [47].