A commando is a soldier who has been highly trained in combat.
In many miliaries, they are used to rescue hostages and board enemy ships. In the United Kingdom, to become a commando, candidates must pass either Royal Marine Commando training or the All Arms Commando Course.
The military of the United States and some other countries, do not have (military) units with commandos. The United States does have special forces soldiers (and they are sometimes called special forces operators). United States Army Special Forces is one of the special forces of the U.S. military.