With this work, we want to provide the photovoltaic (PV) community with guidelines for future research on intermediate band solar cells (IBSCs). After two decades of intense research, the operation principles and the physical processes involved in IBSC operation have been unambiguously demonstrated by international teams worldwide. For this, a vast number of intermediate band (IB) materials, fabricated via different technological approaches, have been studied. The field has reached the necessary maturity to aim for operational, high-efficiency devices. Yet, we feel that, driven by the large number of explored materials and technologies so far, there is some confusion about what route the IBSC should take to go from the proof of concept to high efficiency. In this work, we give our view on which the next steps in IBSC research should be. For this, first we briefly review the theoretical framework of the IBSC, the achieved experimental milestones, and the different technological approaches used, with special emphasis in those recently proposed.