PDCD1 and colorectal carcinoma: Using the CRC tissue microarrays from our center, we subsequently verified how PLCG2 expression was tied to immune cell infiltration as well as PD-1 and PD-L1 expression, and the mIHC results demonstrated that high expression of PLCG2 led to low CD8+ T-cell infiltration and high Treg-cell infiltration, as well as abundant expression of PD-1 and PD-L1.