Healthcare system is rapidly transitioning from a traditional health-center and specialist-focused model to a more scattered, patient-centric model. Medical Internet of Things (MIoT) provides machine-to-machine contact and real-time intervention solutions, which in the near future will drastically revolutionize healthcare delivery, affordability, and reliability. The Medical Internet of Things (MIoT) is a new technology that aims to improve patient quality of life by allowing individualized e-health services irrespective of time or place. The Medical Internet of Things (MIoT), often known as healthcare IoT, is a network of medical devices and applications. MIoT applications are intimately linked to sensitive healthcare services, particularly because they manage sensitive patient information such as names, health records, addresses, and health problems. The key problem in the MIoT area is to protect the confidentiality and privacy of patients without compromising security. The security and privacy of data acquired from MIoT devices, either while transmission to the cloud or while kept in the cloud, are key unsolved challenges, as this data is heavy, sensitive, and require a high level of security. We examine present security and privacy challenges, as well as security and privacy needs connected to data flow in the MIoT, as well as technical shortcomings and research issues for future work, in this paper. Finally, we can state that the growing adoption of the MIoT in recent years has brought enormous benefits to both medical organizations and their patients.