Bias is a preference for one thing over another. Research and data are inherently biased due to preferences for certain perspectives. While researchers try to decrease bias in their work it is impossible to eliminate bias completely. Explicit and implicit (unconscious) bias can be found in data sampling, collection methods, analysis and how the data is shared. Bias is present on a systemic level in what gets researched, published, and cited.
As you are researching your topic ask yourself, what perspectives are being favored? What perspectives are missing? Why? How can you add missing perspectives to your paper?”