The Chinese Communists persuaded the KMT provincial and military leadership to surrender. The Soviet Union induced the leaders of the former ETR to accede to the Chinese Communists. In August 1949, four of top ETR leaders, Ehmetjan Qasim's delegation, died in a plane crash en route to Beijing[1][2][3] to attend the Chinese People's Political Consultative Conference, the Chinese Communists' united front conference. In December, China's new government incorporated the ETR military into the PLA, which marked the end of the independence of Xinjiang's second East Turkestan Republic. Most of the remaining former ETR leadership, i.e. Burhan Shahidi and others, accepted the absorption of the autonomous Three Districts into the newly founded People's Republic of China. They along with the surrendered KMT officials took senior positions in the PRC government.

https://en.m.wikipedia.org/wiki/Incorporation_of_Xinjiang_into_the_People%27s_Republic_of_China

I don't know where the fuck you got that from. Xinjiang was already under joint KMT rule. The PLA got the KMT to surrender and the Soviet Union convinced the local ETR to join the PLA, which they did. There was almost no fighting at all.