Retinal cell therapy is envisioned as a treatment modality to repair the retina and improve vision in people with degenerative or hereditary retinopathies. In pursuit of this goal, transplantation of ES/iPS‐derived photoreceptor precursor cells is being developed as a treatment to replace lost photoreceptor cells. Several studies have shown that photoreceptor precursors can mature and incorporate into the recipient retina following transplantation in the subretinal space. However, knowledge regarding the identity and distribution of transplanted cells is incomplete, and furthermore, how closely the transplanted photoreceptors resemble normal photoreceptors in an intact wild‐type retina is unclear. In addition, a key gap in knowledge pertains to how the recipient retina regulates the maturation, fate specification, and migration of transplanted donor cells. This talk will describe how the subretinal space in the degenerative recipient eye promotes the maturation of transplanted rod and cone photoreceptor cells. In addition, observations of graft‐derived cells that migrate into the recipient retina, including some that travel long distances away from the graft, are presented. These findings highlight that in vitro human micro‐organogenesis can produce complex organoids with unusual and unexpected ectopic components that do not typically comprise the normal organ, and thus can profoundly influence therapeutic studies that use those organoids. These findings demonstrate the importance of the extracellular microenvironment in determining cell identity and behaviour in human organoids being developed for treatment purposes.