Conflict of interest
Various parties have various goals. A person working as a researcher can be focussed at finding truth, but that same person can also be a part of a sports club whose goal is playing sports. So being part of various groups comes with having various goals or interests.
Sometimes these interests contradict each other. In this case one speaks of a conflict of interest.
A conflict of interest in itself is not bad, only when it leads to bias or the appearance of bias.
This section is based on (Koepsell, 2016).