Asthma affects 29 million Americans in 2026 — but over half with moderate-severe disease have uncontrolled symptoms. This guide covers all asthma types, GINA 2026 stepwise treatment, ICS-formoterol as the new reliever standard, a 10-inhaler comparison table, a 12-trigger avoidance table, and all Step 5 biologics including tezepelumab.