Data Detective is an achievement/trophy in Deus Ex: Mankind Divided. It is awarded for completing one of the four darknet files in the Breach mode of Mankind Divided. The first darknet file that becomes available to investigate is one involving VersaLife experimentation on a child with leukemia.
In order to complete a darknet file, you must complete specific nodes related to the case being investigated. The nodes that need to be completed are outlined by ShadowChild.