Imagine a shot that doesn’t just jab at your immune system or carry a vaccine’s instructions, but actually rewrites a faulty line of code inside a living human cell. If you’ve followed the arc of gene editing, that’s no longer sci-fi: in vivo CRISPR therapies delivered by lipid nanoparticles are moving from lab benches toward real patients. This, I’d argue, is one of the clearest breakthroughs of our era—because it promises to treat disease by repairing the patient’s own genes inside the body, rather than removing tissue or editing cells outside the body and hoping them back in. Why now? Only on Breakthroughs!