On September 1, 1982, at the opening of the 12th Party Congress, Deng Xiaoping spoke of the task to “combine the universal truth of Marxism with the concrete reality of our country, take our own road and build socialism with Chinese characteristics.”
The idea had an earlier form. In October 1938, in his report On the New Stage to the Sixth Plenum of the Central Committee, Mao Zedong first spoke of the Sinicization of Marxism. Chinese Wikipedia describes it as combining Marxist theory with China’s conditions, its cultural traditions and its history.