29 patients were enrolled, including 10 patients with Hodgkin lymphoma (HL), 19 patients with other tumor types...Sintilimab was well tolerated without dose-limiting toxicity...Subjects with PD-L1-positive expression benefited more from sintilimab treatment than PD-L1-negative subjects (66.7% ORR versus 33.3% ORR, p=0.314)...Sintilimab was well tolerated and demonstrated promising anti-tumor activity in pediatric HL.