Chronic GVHD (cGVHD) is a major cause of illness in patients who undergo hematopoietic transplantation (HCT). GVHD can affect any organ in the body, can require several years of treatment, and can impact the quality of life (QoL). Physical activity and exercise have been shown to enhance fitness and improve QoL in chronic illnesses including GVHD, however, patients often have barriers to attending sessions including distance, risk of infection, and physical therapists' lack of experience with pediatric patients. The team's goal is to assess whether a virtual rehabilitation program in children post-HCT (including children with chronic GVHD) is feasible and whether its implementation will improve physical functioning and QoL. Patients between the ages of 8 and 23 years who are at least one hundred days post-HCT will be eligible for participation. Patients will have an assessment by a pediatric physical therapist at the time of study entry, at the end of the rehabilitation program, and approximately 3 months later. They will be supplied with some exercise equipment (such as dumbbells and resistance bands). Patients will have twice weekly half-hour one-on-one online sessions with the physical therapist for 12 weeks. Patients will be recruited through the bone marrow transplant clinic.