This study looks at using two drugs, belumosudil and rituximab, to treat a condition called chronic graft-versus-host disease (cGVHD). cGVHD happens when a person's new immune cells from a transplant attack their body. This study is in Phase 2, which means it's checking how safe and effective these drugs are. People can join if they've never been treated for cGVHD, except for taking less than ten days of certain medicines. They also need to be pretty healthy, with good blood and heart functions.

But, if someone has other active infections or certain health issues, they can't join. The study is open-label, so everyone knows what treatment they're getting. Participants will be closely monitored to see how well the drugs work and any side effects.

• Participants need to have a good health condition to join.
• The study checks the safety and effectiveness of the drugs.
• This is a Phase 2 study, focusing on treatment for cGVHD.