Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease that results from SFTS bunyavirus (SFTSV) infection. Infection with SFTSV can activate the immune system, producing a series of inflammatory factors. Some patients, particularly those with pre‐existing conditions or at an advanced age, may experience an excessive inflammatory response, triggering systemic multi‐organ failure progressing to severe disease and, potentially, death. In recent years, extensive research has been conducted on the mechanism of SFTSV infection and its interaction with host immune responses. Additionally, a range of biomarkers with significant prognostic value for SFTS have been identified. This review provides a comprehensive summary of the latest advancements in understanding the interplay between SFTSV and host immune responses, and elucidates the role of these biomarkers in the early detection of severe cases and fatal outcomes. The insights presented aim to inform strategies for early intervention, clinical treatment, and prognostic assessment of patients with SFTS.