RecruitingPhase 2Drug trialA Study to Evaluate Axatilimab Versus Best Available Therapy in Pediatric Participants With Chronic Graft-Versus-Host Disease After at Least 2 Prior Lines of Systemic Therapy (AGAVE-256)This study will be conducted to compare Axatilimab Versus Best Available Therapy in Pediatric Participants With Chronic Graft Versus Host Disease After at Least 2 Prior Lines of Systemic Therapy.