What boundary is Peru-Chile Trench and Andes Mountains?

The Peru-Chile Trench and the Andes Mountains are located along the western coast of South America, but they do not form a boundary between two countries. The Peru-Chile Trench is a deep oceanic trench located in the Pacific Ocean, while the Andes Mountains are a continental mountain range that runs along the western coast of South America. The boundary between Peru and Chile is the Atacama Desert, which is located between the Andes Mountains and the Pacific Ocean.