China, like the old USSR, is a multinational empire held together, in theory, by a shared ideology. OTOH, it is not quite so multinational as the Soviet Union was; its core Han-Chinese population is much larger relative to non-Han minorities (91.9% of the total population – China - Wikipedia) than the USSR’s non-Russian population was relative to non-Russian minorities (50.78% – Soviet Union - Wikipedia; and it has been much more successful in Sinicizing its minority regions than the USSR was in Russianizing its minority regions. The state policy of colonizing non-Han territories with Han (we might call this “ethnic swamping” as opposed to “ethnic cleansing”) has produced a situation where some of the historically non-Han territories now have a very substantial Han minority and most have a Han majority:
Gansu Province: 91% Han, 5% Hui, 2% Dongxiang, 2% Tibetan – Gansu - Wikipedia
Guangxi Autonomous Region: 62% Han, 32% Zhuang, 3% Yao, 1% Miao – Guangxi - Wikipedia
Guizhou Province: 62% Han, 12% Miao, 8% Buyi, several smaller nationalities – Guizhou - Wikipedia
Inner Mongolia Autonomous Region: 79% Han, 17% Mongol, 2% Manchu – Inner Mongolia - Wikipedia
Historic Manchuria:
Heilongjiang Province: 95% Han, 3% Manchu, 1% Korean – Heilongjiang - Wikipedia
Jilin Province: 91% Han, 4% Manchu, 4% Korean – Jilin - Wikipedia
Liaoning Province: 84% Han, 13% Manchu, 2% Mongol – Liaoning - Wikipedia
Ningxia Autonomous Region: 79% Han, 20% Hui – Ningxia - Wikipedia
Qinghai Province: 54% Han, 23% Tibetan, 16% Hui, 4% Tu – Qinghai - Wikipedia
Tibet Autonomous Region: 93% Tibetan, 6% Han – Tibet Autonomous Region - Wikipedia
Xinjiang Autonomous Region: 45% Uyghur, 41% Han, 7% Kazakh, 5% Hui – Xinjiang - Wikipedia
Yunnan Province: 67% Han, 11% Yi, several smaller nationalities – Yunnan - Wikipedia
Give this status quo, do any non-Han secessionists but those of Tibet have even a Chinaman’s chance? I mean, if you held a genuinely democratic referendum on the status of Inner Mongolia, wouldn’t the Han majority vote against independence?