I'll point out that transplants / grafts between identical twins do work without rejection. And that was basically the only type of transplant surgery that occurred before the discovery of immunosuppressants. Isograft: Past that, I've seen papers testing all kinds of coatings and shapes on implanted devices. They delay, but never prevent the inevitable. Personally I suspect that it's not just what cells touch, but how their neighbors respond to that touch that dictates rejection. But that's largely speculation. Home-grown stem-cell-derived tissues might one day be a thing, but until then, we're stuck with sticking metals under our skin. Which I personally regard as dumb when medically unnecessary.That's a 1:1 replacement, blood type and all biomarkers matching perfectly, and the body still knows it ain't natural
An Isograft is a graft of tissue between two individuals who are genetically identical (i.e. monozygotic twins). Transplant rejection between two such individuals virtually never occurs.