Actually, early Chinese Communists were mostly Bolsheviks who had the backing from USSR and who had cast Mao to the sideline.

But eventually, the ROC government cracked down on the Communists, and the Communist military suffered heavy losses in the "5 Extermination Campaigns" waged by the ROC military.

Soon after, Mao staged an overthrow of the Bolsheviks, and took over the CCP leadership, and "Maoism" (an agrarian based form of Communism) took over as the new doctrine of the CCP. This was when CCP parted ways from the USSR based Communism.