This study focuses on helping kids and young adults, aged 8 to 23, who have had a hematopoietic transplantation (HCT). Hematopoietic transplantation is a procedure where a patient receives blood-forming stem cells, often used for treating diseases like leukemia. After HCT, some patients may develop chronic GVHD, a condition where the new cells attack the body, which can make them sick for a long time. The study aims to see if a virtual rehabilitation program can improve how well these patients function and feel. Rehabilitation means helping people get better through exercise or therapy. Participants will have virtual sessions twice a week for 12 weeks with a therapist and will receive exercise tools like dumbbells. This program is designed to be safe and convenient, especially as kids might live far from hospitals. The study will check progress at the start, end, and three months after the program.

• The study lasts 12 weeks with 2 online sessions per week.
• Participants receive free exercise equipment for the program.
• Patients must have internet access and be cleared by a doctor to exercise.