RecruitingPhase 4Drug trialStudy of Efficacy and Safety of Ruxolitinib in Chinese Participants With Corticosteroid-refractory Chronic Graft vs. Host DiseaseThe purpose of the study is to assess the efficacy and safety of ruxolitinib in Chinese adult and pediatric participants aged 12 years or older with corticosteroid-refractory chronic graft vs. host disease (SR-cGvHD).