How Google search results work
https://www.cnbc.com/2018/08/28/how-google-search-results-work.html
Political leanings don't factor into Google's search algorithm. But the authoritativeness of page links that the algorithm spits out and the perception of thousands of human raters do.
In a tweet early Tuesday, President Donald Trump called Google's search results "rigged," claiming that searches of "Trump news" only showed reporting by what he called the "Fake News Media."