A more thorough explanation:

An extradition treaty is an agreement between two countries that outlines the conditions and exceptions for surrendering a fugitive from justice. This means that if someone commits a crime in one country and flees to another, the second country can send them back to the first country to face trial.

For example, the United States has an extradition treaty with Mexico. If a person commits a crime in the US and then flees to Mexico, the US can request that Mexico extradite the person back to the US to face trial.

Another example is the extradition treaty between the UK and the US. In 2019, the UK extradited a man to the US to face charges of hacking into US government computers.

These examples illustrate how an extradition treaty allows countries to work together to ensure that criminals are brought to justice, no matter where they try to hide.