Coccidioides posadasii is a fungal pathogen that causes coccidioidomycosis, also known as Valley fever. This disease primarily affects the respiratory system and is endemic to arid regions of the southwestern United States, northern Mexico, and parts of Central and South America. Coccidioidomycosis can range from mild flu-like symptoms to severe pneumonia and disseminated disease, particularly in immunocompromised individuals. Research on Coccidioides posadasii focuses on understanding its epidemiology, pathogenesis, diagnosis, treatment, and prevention strategies. Additionally, efforts are underway to develop improved diagnostic tools and vaccines for this fungal infection.