This study involves collecting blood, biopsy tissue, and urine samples from people who have had an organ transplant and those who haven't. The goal is to understand how patients respond to transplant medications and improve treatments. A transplant is when a healthy organ replaces a sick one. Biopsy means taking a small piece of tissue for testing. These samples help researchers see how drugs affect the immune system (the body's defense system). The study also compares transplant patients to healthy volunteers. By learning more, doctors can create better medicines with fewer side effects. Participation won't change your treatment or care. If extra samples are available, they will be saved for future research. Joining the study is the first step in helping doctors find the best medications for each patient.

• Participants give blood, urine, and tissue samples for testing.
• The tests are for research only; they don't change your treatment.
• Both transplant patients and healthy volunteers can join.