After watching “Navalny,” the documentary about Russian opposition leader Aleksei A. Navalny, a Chinese businesswoman sent me a message: “Ren Zhiqiang is China’s Navalny.” He was referring to the retired real estate tycoon who was sentenced to 18 years in prison for criticizing China’s leader, Xi Jinping.

After Navalny’s tragic death this month, a young dissident living in Berlin posted on X: “Professor Li is the closest to the Chinese version of Navalny.” He was referring to the rebellious influencer known as Teacher Li, who used social media to share information about the protests in China and who now fears for his life.

There are others: Liu Xiaobo, the Nobel Peace Prize winner who died in government custody in 2017, and Xu Zhiyong, the jurist serving 14 years in prison on subversion charges.

The sad reality is that there is no Chinese equivalent of Mr. Navalny because there is no opposition party in China and therefore no opposition leader.

It’s not for lack of trying. Many brave Chinese stood up to the most powerful authoritarian government in the world. Since 2000, the non-profit humanitarian organization Duihua has recorded the cases of 48,699 political prisoners in China, of which 7,371 are currently in custody. None of them have the kind of recognition among the Chinese public that Navalny had in Russia.

Under President Vladimir V. Putin, Russia is very intolerant of dissent. Putin imprisons his critics and persecutes them even in exile. In China, there could be no counterparts to Navalny as high-profile figures. They would be silenced and imprisoned long before they could reach the public consciousness.

“Can you imagine the People’s Republic of China giving prominent political prisoners the continued access that Navalny had to public opinion through various direct and indirect methods?” Jerome Cohen, retired New York University law professor, wrote in X, in reference to the full name of China, People’s Republic of China.

That was what members of the Chinese dissident community thought as they watched the news of Mr. Navalny’s death with pain and horror. His death was tragic and his life was heroic. But they found it difficult to process revelations that he was able to send hundreds of handwritten letters from prison. People wrote to him for 40 cents a page and received scans of his responses. A video link of him behind bars during his final court appearance was posted online.

“Despite increasingly harsh conditions, including repeated periods in solitary confinement,” wrote my colleague Anton Troianovski, “he maintained a presence on social media, while members of his team continued to publish investigations into the corrupt elite of “Russia from exile”.

None of that would be possible in China. The names of most Chinese political prisoners are censored online. Once arrested, they were never heard from again. No one can visit them except their immediate family and their lawyers, although that is not guaranteed. China’s political prisoners are unable to correspond with the outside world and are left to rot behind bars, even as they struggle with health problems, just as Liu, the Nobel Peace Prize winner, died of late-stage liver cancer while He was in government custody.

Some people call Ren, the retired real estate magnate, “China’s Navalny.” He once had probably the highest public profile among Chinese political prisoners. He was among the most influential social media bloggers in the country, with nearly 38 million followers. In 2016, his Weibo account was deleted after he criticized Xi’s statement that all Chinese media outlets had to serve the party.

Last year, when I mentioned it to a young Chinese man, the man gave me a blank look. He was 15 when Mr. Ren was silenced and had no idea who he was.

I have known Mr. Ren since 2010. But since his arrest in March 2020, I have not had direct communication with him. Neither are his friends. None of us have firsthand knowledge of his life in prison.

Days before his arrest, Mr. Ren told me that he was scheduled for a biopsy for suspected prostate cancer. For months, I have heard people who have contacted his family say that he is not receiving proper treatment for his prostate conditions and that he gets up a dozen times a night to go to the bathroom. I cannot communicate with members of his family because giving interviews to foreign media could cause problems for them.

Gao Zhisheng was a human rights lawyer who spent years in prison, was tortured, and then disappeared in 2017. His family has not heard from him since. No one knows his whereabouts or even if he is alive. At this point, very few Chinese know his name.

“Their disappearance is common” wrote Guo Yushan, an activist who helped lawyer Chen Guangcheng seek asylum in the United States in 2012. “The system drives them to extinction, the broader society rejects and protects them, and the public forgets them,” Guo said. “And often, the more intense their resistance, the more complete their disappearance.”

Guo wrote those words in 2013, the first year of Xi’s rule, for an organization that offered financial assistance to families of political prisoners. Programs of this type would be unimaginable in today’s China. Mr. Guo himself disappeared from public view after being released from nearly a year of detention in 2015.

In a society as tightly controlled as China under Xi, it is impossible for anyone to have the kind of influence that Navalny had. The Communist Party’s greatest fear is organizations and individuals who may challenge its rule. That’s why he doesn’t like religious groups or non-governmental organizations. He fears businessmen who he believes have the financial power and organizational skills to pose a threat to the party.

Put out any sparks that could turn into a prairie fire.

At the moment he seems to be obsessed with Teacher Li, a social media influencer with a cat avatar. Li Ying is a painter who in 2022 turned his Twitter account into a one-man news hub, informing the Chinese public of news they don’t get from heavily censored media outlets or the Internet. This week, he urged his followers in China to stop following him because police questioned some of them. In one day, the number of his followers fell from 1.6 million to 1.4 million.

Mr Li, who lives in Milan, told me last year that he was psychologically preparing himself for the possibility of being murdered.

Russia has been learning from China how to exert control over its people in the age of social media. It has blocked most major Western platforms except YouTube since its invasion of Ukraine two years ago. With the death of Navalny, the opposition’s most prominent figure, it could be difficult for other opposition leaders, mostly in exile, to gain a national following as he did.

Regardless of the different forms of authoritarianism they face, Russian and Chinese political prisoners share the aspiration that their countries are not doomed and become normal, democratic and free.

They are all Navalny.

Navalny decided to return to Russia despite knowing he would be arrested. Xu Zhiyong, the jurist who is serving 14 years in prison, made a similar decision.

In 2013, he wrote in an essay that between home and prison, he chose the latter. It was a painful choice for him, but he felt that he couldn’t not make the decision he did. After leaving prison in 2017, he said, he was ready to return.

“For many years,” he said. wrote on January 1, 2020, “I’ve been thinking about what would be more valuable to my country: staying in jail or staying out of it.”

A month later, he was arrested again.