A few years ago my computer science professor went on a tangent about a colleague of his working on scaffolding apparently they were working on trying to create an agnostic cartilage material that would be in theory treated with indifference by the immune system. And that onto that material the cells of an organ could be sprayed on. The idea, (and I admit that it was explained in a high concept without details.) was that you would use the healthy liver cells of the subject to in practice grow a new liver. Thereby bypassing Immuno suppressors

That was back in 2016, I am not sure how far along that research currently is. But when we were told about it the outcome was not optimistic until 2030's.