A mission is also a group of people who are sent to another place to do a particular job or to represent their country, organization, or religion, or the place where they go to do this work:
A mission is an important task that people are given to do, especially one that involves traveling to another country. Salisbury sent him on a diplomatic mission to North America.
There are 18 meanings listed in OED's entry for the noun mission, one of which is labelled obsolete. See ‘Meaning & use’ for definitions, usage, and quotation evidence.
MISSION definition: a group or committee of persons sent to a foreign country to conduct negotiations, establish relations, provide scientific and technical assistance, or the like. See examples of mission used in a sentence.
To send (someone) on a mission. 2. To organize or establish a religious mission among (a people) or in (an area).