PDCD1 and gastric cancer: Recently, multiple RCTs have shown that PD-1 blockade plus chemotherapy outperforms chemotherapy alone as a first-line therapy for patients with advanced GC, especially for those with high PD-L1 expression levels (Janjigian et al., 2021; Kang et al., 2022; Moehler et al., 2023; Rha et al., 2023; Xu et al., 2021; Shitara et al., 2020).