At first, scientists grow humanized kidneys:

In a groundbreaking achievement, scientists have grown a humanized kidney
for the first time. This remarkable development holds tremendous promise
for organ transplantation and regenerative medicine. By using cutting-edge
techniques in tissue engineering and stem cell research, researchers
created a functional kidney that closely resembles the complexity and
functionality of a natural human organ. This breakthrough could
revolutionize how we address organ shortages and improve the lives of
countless individuals awaiting kidney transplants.