Over the last two decades, there has been a strong interest in the cosmic ray positron fraction which exhibit an excess of high energy positrons whose origin is still highly uncertain. The Alpha Magnetic Spectrometer (AMS-02) is a general purpose high-energy particle physics detector operational on the International Space Station since May 2011. During its unique long duration mission, AMS-02 is collecting large amount of data to study the behavior of cosmic ray electrons and positrons with unprecedented precision. The latest measurements of positron fraction, positron flux and electron flux with AMS-02 will be presented, and the interpretation of the positron excess in terms of pulsars or dark matter will be discussed.