Answer:
It was breaking of political relationships between People's Republic of China and (PRC) and the Union of Soviet Socialist Republics (USSR) from 1956 to 1966. The split resulted from different interpretations and practical applications of Marxism and Leninism.
Impact:
The Cold war which was initially bi-polar (between USA and USSR) now became tri-polar (USA, USSR, and PRC).
The cultural revolution (Great Proletarian Cultural Revolution 1966–1976) of China launched by Mao Zedong.
Sino-Soviet border war
Nuclear China
Step-by-step explanation:
The main impact which Sino-Soviet split had on cold war was that Western world led by USA initially (before the split) had to prevent USSR from gaining influence in the rest of the world, and counter USSR's increasing military power. However with because of this split China also started feeling itself unsafe from USSR, and started increasing its military power and political influence in the world. China testing its atomic bomb (October 1964) was also a direct result of the split.
In short Western world led by USA now had two fronts instead of previously one.