In contrast to conventional power systems dominated by synchronous generators, the renewable-based power system is characterized by grid-connected inverters and exhibits distinct dynamics. Numerous incidents of unidentified instability have been frequently reported. Oscillation phenomena across a wide frequency range occur, exhibiting the features of nonlinear, time-varying, and complex dynamics. This paper aims to provide a comprehensive overview of impedance passivation methods for grid-following and grid-forming inverters. It delves into strategies such as controller optimization, virtual impedance reshaping, and other advanced passivation techniques. The research limitations and the persistent challenges to be addressed are finally concluded.