PDCD1 and gastric cancer: Ferrara [12], Aoki, and colleagues [13] observed that in patients with NSCLC or advanced gastric cancer (AGC), HPD was more common among anti-PD-1/PD-L1 monotherapy cohorts compared to the chemotherapy cohorts, and that patients with HPD showed poorer prognosis than patients showing progression without HPD in the anti-PD-1/PD-L1 therapy cohorts.