Ironically enough, the major impact of the Cuban Missile Crisis was to lower tensions between the United States and the Soviet Union.  There were other relatively minor impacts, but this was the most important impact.

One set of minor impacts was felt by Cuba.  First, it was protected from US invasion.  The US promised not to invade Cuba as part of the settlement of the crisis.  Second, however, the Cubans felt somewhat betrayed and used by the Soviets.  They felt the Soviets had not consulted with them during the crisis.  This harmed Cuban-Soviet relations to some degree.

The main impact, in terms of world history, was the reduction in tensions between the US and the USSR.  The two sides realized that it was in no one’s interest to come that close to war.  Therefore, they did things like setting up the hotline between Washington and Moscow to prevent the escalation of any future crises.  We can argue that this close call in Cuba helped to prevent the US and the USSR from coming anywhere close to such a dangerous point in the years to come.  Even when the US was fighting in Vietnam and the Soviets were helping our enemies, we never came close to another crisis.  This may be the most important effect of the Cuban Missile Crisis.