Recently, rapid advances in wireless communication technology led to arrive internet of things (IoT) which is next generation of information and communication technology (ICT). IoT network is composed of different devices with different wireless communication technologies. In this environment, each device can suffer from interference from other devices, and it can be the major reason of significant performance degradation. In addition, the number of devices dramatically increase due to advent of IoT paradigm, and each communication technology has different characteristics such as data rate, signal strength, power consumption, and channel composition. Thus, above problem of performance degradation may be intensified. More specifically, a communication technology which transmits with lower signal strength has more sensitive for external interference from other communication technologies which transmit with higher power. However, interference mitigation schemes for coexistence problem considering IoT environment are not exist, and the existing interference mitigation schemes for traditional communication technologies cannot be directly applied to IoT environment because they do not consider external interference from different communication technologies. In this paper, we first introduce coexistence problem which is the major reason of network performance degradation due to external interference, and we also analyze existing work for mitigating interference in traditional wireless networks. Based on results of analyzing existing interference mitigation scheme for coexistence problem in traditional wireless network, we suggest research direction considering with coexistence situation in IoT environments.