Writers for the New York Times, Fox News, and the Wall Street Journal can cover the same event, but because they have different perspectives, include details that make their stories sound conflicting. Similarly, the gospels are the same story, written from the viewpoint of four different authors.
For example, Matthew, a Jewish tax collector, focused on how Jesus fulfilled prophecies, validating His claims to the Jewish people. By contrast, Luke was a Greek historian so his narrative flows like a documentary, putting a name and face on the events as they happened.
Because we have varied accounts of the same events, we know the writers were not in collusion - which adds credibility to their story.