Okay, so there is something called the "second amendment" in the United States. This is a part of the constitution and it says that people have the right to own guns. Some people feel really strongly about this right and don't want anyone to take it away from them.
So, they have decided to create "second amendment sanctuary" areas. This means that they want their town or city or state (which is like a big group of towns and cities) to be like a sanctuary, which is a safe place. But instead of being safe for animals, it's safe for guns!
Basically, the people who live in these areas want their leaders (like the mayor or governor) to promise that they won't make any laws that would take away their right to own guns. It's like making a special rule for that place that's different from the rest of the country. It's like saying, "This is our safe space for guns and we want to protect it."