While aggregated mobile device location data have been extensively used to model SARS-CoV-2 dynamics, relationships between mobility behavior and the transmission of other respiratory pathogens are less understood. Understanding the influence of human mobility on endemic pathogens is crucial for predictive purposes, especially as perturbed circulation can lead to overlapping epidemics of different pathogens, putting extreme strain on healthcare systems. In this seminar, I will present research investigating the effects of population behavior on the transmission of 17 endemic viruses and SARS-CoV-2 in Seattle, Washington, during pre- and post-pandemic years, using detailed data from a citywide respiratory pathogen surveillance study and high-resolution cellphone mobility data. I will highlight mobility metrics that are consistent leading indicators of outbreaks and compare patterns across pathogens with different transmission modes, seasonal cycles, and age distributions of infection. Additionally, I will discuss recent work linking the evolutionary and epidemiological dynamics of influenza in the US and future plans to explore the effects of decreased social distancing and waning immunity on the post-pandemic reemergence of respiratory syncytial virus (RSV) in Seattle.