The term 'Cloak-and-Dagger Group' refers to a group of spies who operate in secret and use deception and subterfuge to achieve their goals. This type of espionage has been used for centuries, but the term itself was first used in the early 20th century. The term is derived from the use of disguises and hidden weapons, such as daggers, to conceal the identity of the spies. The group typically consists of highly trained individuals who are experts in the art of espionage and covert operations.