Those millions Chineses are invisible, no single Chinatown in all Siberia. According to official statistic there are circa 50 000 Chinamen in all Russia while about half of million Russians from Far East and Siberia moved to China in last decade.70% of Russian territory are frozen swamps.
Russia's Interior Ministry estimates over 2 million Chinese live in Siberia. And there are many, many more arriving every day. In another 20 years, Siberia could be majority Chinese.
The areas of Siberia bordering Mongolia and China are quite remarkably like Mongolia and China, rich in minerals, timber and quite a bit of fossil fuels. All of which China covets. It's going to be the hot spot in Asia in the next decade, in my estimation.