CD274 and colorectal carcinoma: In CRC, PD-L1 has distinct subtypes (e.g., PD-L1a, PD-L1b, PD-L1c) and soluble variants (e.g., PD-L1v229 and PD-L1v242) that act as decoys, Facilitating immune evasion by promoting PD-1/PD-L1 interactions [138,140,141,142].