Species interactions drive patterns of coexistence in communities, but are also environmentally dependent, making measuring and predicting the strengths and effects of these interspecific inter- actions challenging. A variety of approaches such as food web theory, modern coexistence theory, and structural theory are used to tackle these ideas across different systems, but there can be chal- lenges connecting theory with empirical work. Recent advances in community ecology are working to bridge this gap, making steps to increase our mechanistic understanding and predictive power of where and how species coexist. These studies highlight the importance of species interactions in understanding community diversity, species responses to disturbance, and the success or failure of conservation efforts. We propose a session bringing together researchers who are connecting different theories of coexistence or species interactions to empirical patterns, including some researchers who use empirical data to test and extend theory, and other who apply theory to better understand real-world processes.In a changing climate, species interactions are key drivers of population shifts, community dynam- ics, and ecosystem function. Additional interactions with introduced or range-expanding species can further impact communities, with the ability of native species to coexist with the new arrivals a main question of research and management concern. Fitting with the meeting theme, ”A Change is Gonna Come”, multiple participants in our proposed session will address species interactions and coexistence in the context of global change, including warming temperatures and drought events. Additional talks will incorporate non-equilibrium and transient dynamics into previously equilibrium-focused theory, an important step for thinking about ongoing ecological change.