After reaching its climax at the time of Cuban Missile Crisis the Cold War entered into a phase of Detente (peace).By 1970s the new outlook has emerged in USA that the policy of confrontation was not producing the result. The American leadership had realized the limitation of the policy of confrontation and looked for new mechanism to counter balance the threat of communism.
USSR was also facing the economic crunch due to participation in Arms race. The precious economic resources were diverted from economic development to development of military forces. The Soviet economy was passing through a state of crunch and the Soviet leadership was looking to come out of this complex crisis.
The Non-Aligned Movement also played important role in improving the relation between capitalist and communist blocks. This movement served as a buffer between the two super powers and played an important role in opening the channels of communication.USA had recognized the Chinese communist government and was allowed to become member of Security Council.
The Helsinki Agreement of 1975 was also manifestation of improved relations. By this agreement both the groups promised to respect mutual frontiers in different parts of Europe.