The fifth circuit court of appeals has been described as "a collection of 4chan posts wearing robes." It has a reputation for very conservative decisions that are poorly reasoned. And in fact I think it is currently the most overturned circuit at the Supreme Court.

The 5th circuit covers the geographic territory of Louisiana, Mississippi, and Texas. In the US appellate system, the decisions of each circuit are binding precedent within their territory. So the interpretation of the law can literally change if you move to a different part of the country. The Supreme Court is supposed to step in when these "circuit splits" occur, but sometimes it's slow to do so.

In this case, the effect is nationwide because it's an APA case. The court is ordering the FDA to reverse one of its regulatory policies. And the FDA can be sued in any of the 50 states because they operate in all of them.

Edit: I'm just assuming that OP is talking about the mifepristone decision that just came out. But they could be talking about the Louisiana Callais decision on redistricting instead.

they recently banned a abortion pill in the 5th circuit states, mifespristone)