China's search engines have censored the names of leaders of the Communist Party of China and the PRC government for over a decade (see: http://blog.feichangdao.com/2012/12/how-other-websites-are-censoring.html). They typically do this by restricting search results to a white list of around 20 websites under their own control or under the direct control of the central government and the Communist Party. This is illustrated below with a screenshot showing that a search for "Xi Jinping" in Chinese characters (习近平) on Baidu returns millions of results (left), but the same search limited to educational websites returns no results (right).
Paging through the result one finds that the only websites shown are Party and government mouthpieces such as Xinhua, the People's Daily, the China Daily, CCTV (the state controlled television broadcaster), CRI (the state controlled radio broadcaster), etc. This censorship is done for searches of leaders names in Chinese characters and in pinyin romanization (e.g. "Xi Jinping").
The screenshots below show that some time between April 2020 (left) and September 2021 (right) Baidu changed how it was censoring search results for "Xi Jinping" in pinyin romanization. Whereas in April 2020 Baidu was limiting results to the Party/Government white list, it claimed to have found almost 6 million results. In September, Baidu was still limiting search results to that white list, but was only displaying nine results.
At least Baidu is showing something. As the screenshots below show, China's two other major search engines - Qihoo (left) and Sogou (right) return no results whatsoever.
Interestingly, it is still possible to "trick" Sogou into showing search results containing "Xi Jinping" by entering his name in Chinese characters into its English language search engine. The screenshot below shows that in that case Sogou returns dozens of results (again, from the Party/Government white list).