PDCD1 and nasopharyngeal carcinoma: In the first-line anti-PD-1 plus chemotherapy GC cohort, the first-line anti-PD-1 plus chemotherapy advanced or metastatic ESCC cohort and the postline anti-PD-1 monotherapy advanced NPC cohort, higher plasma FGL1 levels were negatively correlated with the anti-PD-1 blockade therapy response (Fig. 2I, J).