A wireless body area network (WBAN) has gained access in monitoring of health conditions of patients. WBAN is applicable in all types of domains like an ambulance (vehicle) to ambulance communication in which one ambulance passes information to another for accessing the road on the priority-basis. The reason is that the ambulance has a patient with critical health conditions. The exchanging of messages between ambulances is supported with the use of an upcoming technology, known as IoT (Internet of Things). IoT motivated for transmission of the monitored vital signs of patients across the Internet. To accomplish this objective, we introduce healthcare-IoT which cares to transmit the reading of vital signs of patients with prioritization. Moreover, this chapter introduces WBAN and its applications in various areas. Subsequently, this chapter shows how to monitor vital signs of patients and sends the detected reading of vital signs of patients to medical doctors for optimal actions. There are routing and medium access control protocols discussed in detail with pros and cons regarding dissemination of patient's data toward the body coordinator and medical staff. In the same way, IoT has introduced to cover up the limitations of WBAN in transmission of data with the architectural design. At the end, some open challenges are discussed of WBAN and IoT.