A more thorough explanation:

An ambassador is a high-ranking diplomat who represents their government in a foreign country or international organization. Their main job is to maintain good relationships with the host country and promote their own country's foreign policy. Ambassadors also work to protect their citizens living in the host country and build strong economic and diplomatic ties with other nations.

For example, the United States has ambassadors in many countries around the world, such as Japan, France, and Mexico. These ambassadors work to strengthen the relationship between the United States and those countries, promote American interests, and protect American citizens living or traveling in those countries.

Ambassadors have diplomatic immunity, which means they are protected from prosecution in the host country for the duration of their time as ambassador. This is important because it allows them to do their job without fear of legal repercussions. However, there are some exceptions to this immunity, such as if the ambassador is involved in a private property dispute or a commercial activity outside of their official duties.