Respiratory infections, a major global health burden, demand deeper insights into host immune defenses to combat emerging pathogens and chronic diseases. This chapter summarizes current knowledge on dual immune system in protecting against respiratory pathogens while avoiding excessive inflammation. Key components of the innate immune system recognize pathogens via PRRs and initiate rapid responses. The adaptive immune system orchestrates pathogen-specific immunity through antibody production, cytotoxic activity, and memory cell formation. Cytokines, chemokines, and immune checkpoints tightly regulate the interplay between these systems to balance defense and tolerance. Dysregulation of these processes contributes to immunopathology in conditions such as influenza, COVID-19, and COPD. The chapter also discusses translational implications, including vaccine design leveraging mucosal immunity, monoclonal antibody therapies, and immunomodulatory agents targeting cytokine storms or immunosuppressive states. By integrating insights from recent advances in single-cell genomics and microbiome research, this chapter emphasizes personalized approaches to increase therapeutic precision. Deciphering the immune landscape of respiratory infections paves the way for innovative strategies to bolster host defense while minimizing collateral damage, offering a roadmap for next-generation interventions in public health.