Yes they are very biased now and it becomes easier every day for that to happen because the people are becoming the same way. There are no true "news " reporting companies left in the mainstream media, to find non slanted stories is nearly impossible.
The Cambridge Analytica story you mentioned is a prime example, the news reporting on that made it sound like that was the first time it ever happened, where FB data was used to influence an election. The truth of that matter is that is was the first time a Republican candidate was able to get the data and use it. When Barrack Obama was running for president FB willingly shared information with that campaign and the folks in his campaign were bragging about how they owned social media and were able to connect with the voters using it. I recently heard some clips from back in that time frame where his campaign people from that time were telling how they worked FB users with targeted advertising to get the people to the polls to vote for Obama.
It is only a problem now that Trump was able to do it, his people were smart enough to use a outside company to work through because FB would never had knowingly supplied his campaign with information that could help him. He turned the tables on them, that is the true problem, not that FB shared or sold data, they sold it to the wrong people.
But you won't be seeing or reading that in the mainstream news, you have to dig to find that information. The majority of people who rely on mainstream media will not have the foggiest idea that this has been done before in presidential elections.