Trump signed an executive order to put it in place later. Biden on day one paused everything to vet whether it aligned with where he wanted to steer the country. He decided to not do that by something as flimsy as an executive order and made it a piece of a big bill that was signed into law, protecting it beyond the whims of a future president. Trump’s administration deserves credit for mobilizing it, but executive orders probably don’t have the teeth to actually make that idea come true and definitely are far from permanent. Now it is the law of the land, and that’s because it went through both parts of Congress and then was signed into law. It is indisputable that charging more for insulin is against the law, and this law was a textbook case of legislating constitutionally. Big pharma has no grounds for suing or not complying, but they might’ve if it were just an executive order.