The US and USSR were trying to complete a back channel deal during the Cuban Missile Crisis.
This all started with the Soviet Union putting missiles in Cuba, which is a mere 90 miles away from the US. This worried the American government, as they felt that the Soviets were preparing for nuclear warfare against the US. In order to avoid catastrophe, John F. Kennedy (president of the US) and Nikita Khrushchev use back channel discussions in order to make an agreement. Essentially the US pledges to not invade Cuba as long as the Soviet Union removes their missiles under the inspection of the United Nations. Along with this, the US agrees to take their missiles out of Turkey 6 months after the missiles are removed from Cuba.