Harran, Oran and The Plague
I've read Camus's "The Plague" recently, and I noticed the similarities in themes and names with Dying Light.
For example, Harran and Oran sound very similar fonetically, and they both had outbreaks, one with the Harran Virus, the other with the Plague. Both stories follow a number of individuals and their own choices. Some profit off of the outbreak, and find a thrill in it, like Cottard and Rais. Others have turnarounds, like Crane with the GRE, and Rambert, with his own survival. And others just try their best to help, like Brecken and Rieux.
I also believe Oran in itself inspired Harran's city, as they both have their similarities, in terrain, worldbuilding, and architecture too.
I definitely think The Plague was a huge inspiration to Dying Light as a whole, both with characters, stories, themes, and even names. That's how I look at it, and I'm quite surprised to not have found any theories on this.