In this paper, we introduce PriMO-5G which is an EU-Korea collaboration project studying the use of 5G technologies and unmanned aerial vehicles (UAVs) or drones to enhance the safety and efficiency of firefighting operations. We start by describing envisaged use cases of smart firefighting focusing on how the 5G communications with drones can help the firefighting. Inspired by the use cases, we identify several research challenges that call for new solutions in 5G radios and cores for mission-critical services. Then, a discussion of a new framework for defining key performance indicators (KPIs) follows. Finally, we introduce our effort and future plans for the demonstration of the technologies that the PriMO-5G develops.