PDCD1 and hypothyroidism: The main findings from the pooled analyses were as follows: (1) PFS was better in patients receiving PD-1/PD-L1, especially within the subgroup of patients with dMMR; (2) OS showed a significant difference favoring PD-1/PD-L1 group beyond 18 months in dMMR subgroup, while no difference was observed for patients with pMMR; and (3) adverse effects such as nausea, rash, fatigue, peripheral neuropathy, constipation, diarrhea, dyspnea, anemia, neutropenia, arthralgia, and hypothyroidism were noted in both treatment groups.