Mao lives until 1993...
First, a longer Cultural Revolution. It's likely the Gang of Four would make him into a figurehead in his last years, but before then they would have destroyed roughly half to two thirds of Chinese relics. So ruins everywhere if you're lucky.
Second, large scale purges a la Stalin. You might result in a hardcore Maoist leadership, with reformers like Deng Xiaoping dying earlier.
Third, somewhere down the line, some provinces will revolt. That triggering point might not even have to be Tibet or Xinjiang. Guangxi is one that comes to mind.
Fourth, any combination of the Soviet Union, the United Kingdom, the United States, Portugal might do an intervention.
Fifth, China might collapse. The nation will not be able to support its own population, since high birth rates are to be expected in an agriculture based economy.
As to Tupac, he doesn't even need to live to see 100. He was 25 when he died in 1996. Extend his life by 25 years, and mumble rap would be strangled at its birth.