The effectors delivered by plant pathogens are crucial for pathogenesis on susceptible host plants, but they can activate an effector-triggered immune (ETI) response on resistant plants. As such, the individual complement of effectors carried by the pathogen and the diversity of Resistance genes carried by the host shapes the outcome of plant-pathogen interactions and drives an arms race that has resulted in a remarkable diversity of pathogen virulence strategies and host detection mechanisms. We have developed systems-level assays to study the diversity that exists within plant-microbe interaction systems and integrate that knowledge into our understanding of plant immunity and disease. We recently explored the extent to which ETI provides species-wide resistance against P. syringae using a compendium of P. syringae effectors (PsyTEC) that represents the pan-genome global diversity. This study showed that ETI is pervasive in the model plant Arabidopsis thaliana against P. syringae, and that ETI can contribute to broad spectrum pathogen resistance. I will present our recent systems-level investigations of plant immunodiversity within and between host species using PsyTEC to map the ETI landscape of closely related wild and domesticated plants. I will also present our studies on how effector effector suites work together to influence plant-pathogen outcomes at the individual and community levels.