**6. Conclusions**

This chapter focused on the advantages of using organoids to expand our knowledge in the field of cellular interactions. We have focused specifically in immunology and disease-related research, going through some of the latest or more relevant publications involving organoids. Overall, organoids constitute an efficient tool to study immune cells´ interactions *in vitro* in 3D-tissue models that provide a closer view of the interactions taking place *in vivo*. Moreover, organoids represent a promising approach in the development of autologous tissue-based cellular therapies, especially in life-threatening diseases. Nevertheless, despite the organoids relevance, the growing interest in these structures and their potential applications, there is still a long way to go to achieve the translation of organoids into clinical practice. The development of bioengineering tools such as microfluidic organ-ona-chip platforms or 3D bioprinting systems represents a huge step in this direction. These strategies could provide consistent nutrients and factors required to emulate 3D tissue physiology *in vivo*. The optimal conditions are not yet established and further research is required before results can be undoubtedly extrapolated and clinical applications implemented. Nevertheless, the growing interest in organoids commercialization will probably help to speed up the translation of organoids to the clinic.

## **Acknowledgements**

This study was supported by the Institute of Health Carlos III, ISCIII (PI16- 00784), and the Programa Operativo de Andalucia-FEDER, Iniciativa Territorial Integrada ITI 2014-2020, Consejería de Salud, Junta de Andalucía (PI0026-2017), co-funded by European Regional Development Fund "A way to make Europe".
