PUP.Optional.Wajam is the detection name for Wajam, a browser add-on marketed as a “social search.”
This is a detection for a potentially unwanted software issued by Amazon “to help you compare products and prices while searching and shopping online.”
Malwarebytes can remove this potentially unwanted software without further user interaction. Should users wish to keep it, they can add the detections to the exclusions list. Here’s how to do it.