uBlock Origin (not to be confused with uBlock which is a different project) is an independent and open-source ad blocker relying on a curated list of servers. It prevents your browser from connecting to these servers to serve you ads.
Note: There are many ad blockers on the market and you can test alternatives. By using an independent, open-source and free ad blocker, you are more likely to avoid products with conflicts of interest, spywares or blockers with "acceptable ads" programs…