Yang is not the first person to speak about "human capitalism". There are plenty of other sources, even a relatively recent book Human Capitalism. Maybe he has been inspired by their usage of this word, but in the end it's simply a statement that he wants to reconcile capitalism with human needs.
On his own Internet page as candidate, one can read:
Capitalism as an economic system has led to unparalleled innovation and improvement in the human condition. Many consider it to have “won” the war of ideas against socialism, but that simplistic view ignores that there is no such thing as a pure Capitalist system. And our current version of institutional capitalism and corporatism is a relatively recent development.
Our current emphasis on corporate profits isn’t working for the vast majority of Americans. This will only be made worse by the development of automation technology and AI.
We need to move to a new form of capitalism – Human Capitalism – that’s geared towards maximizing human well-being and fulfillment. The central tenets of Human Capitalism are:
Humans are more important than money
The unit of a Human Capitalism economy is each person, not each dollar
Markets exist to serve our common goals and values
The focus of our economy should be to maximize human welfare. Sometimes this aligns with a purely capitalist approach, where different entities compete for the best ideas. But there are plenty of times when a capitalist system leads to suboptimal outcomes. Think of an airline refusing to honor your ticket because they can get more money from a customer who purchases last-minute, or a pharmaceutical company charging extortionate rates for a life-saving drug because the customers are desperate.
Thus, he is likely to pursue policies which will be decried as "Socialist" by a large part of the political spectrum in the USA, while he is distancing himself from real Socialists who don't believe in free markets. I think that this program looks rather "European". In fact, I think it falls perfectly in line with the tenets of the "soziale Marktwirtschaft" ("social market economy" aka. Rhine capitalism) in Germany.