Simply put, extradition is the process of handing over a person accused or convicted of a crime to a foreign state/country where the crime was committed. The Philippines and the US have an extradition treaty signed in November 1994 (ratified in November 1996), with Presidential Decree No. 1069 issued in January 1977 being the relevant law.
PD 1069 states that “the suppression of crime is the concern not only of the estate where it is committed but also of any other state to which the criminal may have escaped, because it saps the foundation of social life and is an outrage upon humanity at large, and it is in the interest of civilized communities that crimes should not go unpunished.”
https://www.philstar.com/opinion/2018/08/05/1839677/extradition-treaty-united-states