PDCD1 and cancer: The scatter plot shows the relationship between the Th1 and Th2 scores and expression values of the three genes (CD274 (PD-L1), PDCD1LG2 (PD-L2), and PDCD1 (PD-1)) that were considered as cancer immunotherapy genes involved in the PD-L1/PD-1 axis (Figure 1).