Okay kiddo, do you know what a cell phone is? It's like a little computer that you can use to talk to people and do things like play games or look up information on the internet.
When you use your phone to make calls or send messages, your phone connects to nearby cell towers so that it can communicate with other phones or the internet.
The government wanted to find out where someone was at a certain time, and they thought they could do this by looking at records from the phone company to see which cell towers someone's phone connected to. This is called "historical cell site data" because it's a record of which cell towers someone's phone connected to in the past.
But some people didn't want the government to be able to look at this information without a warrant, which is like a permission slip saying it's okay to look at someone's personal information. They argued that this was a violation of their privacy rights.
So, the court had to decide whether it was okay for the government to access this historical cell site data without a warrant. In the end, the court said that the government needed a warrant to access this kind of information because it was considered private and personal.