Whether or not microbes in the lung exceed a host’s capacity to maintain pulmonary homeostasis depends on a complex integration of physiological processes, together which aim to prevent the onset of pneumonia. For these processes to be effective they must provide adequate levels of both immune resistance and tissue resilience (407). Immune resistance refers to the eradication of living pathogens during an infection, whereas tissue resilience involves the prevention of or resolution of injury resulting from the pathogen and/or from the host response to the pathogen. Inappropriate amounts of either disrupt homeostasis, making both equally essential. Despite important advances in our understanding the pathways comprising resistance and resilience, the degree to which certain biological signals under certain circumstances in certain individuals collaborate to dictate pneumonia outcome remains largely unclear.