The prisoner's dilemma is a paradox in decision analysis in which two individuals acting in their own self-interests do not produce the optimal outcome. The typical prisoner's dilemma is set up in such a way that both parties choose to protect themselves at the expense of the other participant. As a result, both participants find themselves in a worse state than if they had cooperated with each other in the decision-making process. The prisoner's dilemma is one of the most well-known concepts in modern game theory.
The prisoner’s dilemma presents a situation where two parties, separated and unable to communicate, must each choose between co-operating with the other or not.
The iterated prisoner's dilemma is an extension of the general form except the game is repeatedly played by the same participants. An iterated prisoner's dilemma differs from the original concept of a prisoner's dilemma because participants can learn about the behavioral tendencies of their counterparty. Since the game is repeated, one individual can formulate a strategy that does not follow the regular logical convention of an isolated round.
The iterated prisoner's dilemma at times has been called the Peace-War game.
This video is a pretty good example / explanation of the iterative game: Iterated Prisoner's Dilemma and The Evolution of Cooperation. The narrator speaks a little fast in my opinion, but there is a lot of information in a relatively short period of time.