Kyle Busch's cause of death: severe pneumonia and sepsis

Kyle Busch is gone. The NASCAR legend died in May, and now we finally know why. Severe pneumonia triggered sepsis, which his body couldn't fight off.

Pneumonia hits fast. You catch a respiratory infection, it gets worse instead of better, and suddenly your lungs are filling with fluid. When that spreads into your bloodstream and triggers sepsis, your organs start shutting down. Busch's medical team tried everything, but his body had already crossed the line.

This hits different when it's someone you watched on track for decades. Pneumonia and sepsis take thousands every year, especially people whose immune systems are already stressed. Busch was 58. The racing community is still processing the loss.