Okay kiddo, so basically in 2015, the United States and China made an agreement about how they are going to behave when it comes to using the internet and computers. They agreed that they wouldn't use the internet to spy on each other or do bad things to each other's computer systems. This is really important because both the United States and China have lots of important information on their computer systems, and it would be really bad if someone hacked into them and stole that information. So this agreement helps to make sure that both countries are playing fair when it comes to using the internet and computers.