PD-1/PD-L1 was detected to be overexpressed in NSCLC patients, and high expression of F-FDG PET/CT and PD-L1 was positively correlated with poor disease free survival (DFS) (Grizzi et al., 2019; Wang et al., 2020). The gene discussed is PDCD1; the disease is non-small cell lung carcinoma.