Pulmonary sarcoidosis is a multisystem disease characterized by non-caseating granulomas. Its pathogenesis involves genetic susceptibility and abnormal immune responses triggered by environmental antigens. The article provides an overview of the immunological etiology and mechanisms of pulmonary sarcoidosis. It systematically discusses the pathogenetic basis, basic immune mechanisms and the role of key immunological biomarkers. Biomarkers include sIL-2R, CD4+/CD8+ ratio in BALF and HRCT. These are used for diagnosis and assessment of the disease. It outlines a step-by-step therapy from glucocorticoids to immunomodulators and biologics to new antifibrotic therapies. The aim is to provide an immunological basis for accurate diagnosis and treatment of pulmonary sarcoidosis.