Prisoner of War (POW) is a member of the armed forces or any person fighting for the cause that has been captured by the enemy, during an armed conflict.
Missing in Action (MIA) is a soldier who has gone missing while serving. It is unknown what has happened to the soldier. The soldier may be dead, injured, or captured. If they have died neither a grave or their body can be identified.
In past centuries prisoners had no rights and usually became slaves of their enemies. They were often tortured or beaten to death . Today prisoners of war have rights that are to be followed internationally. However, enemies don't always follow and therefore commit war crimes.
National League of POWMIA Families​. (2020). Retrieved 18 September 2020, from https://www.pow-miafamilies.org/