A Microchip implant covers a range of technologies for placing tracking or processing devices into humans. They may be used in a military, corporate or personal context.
Current generation technologies function primarily as a convenience for the user, as the unique identifer transmitted is easy to clone and spoof in a security context.
Grinders choose to voluntarily augment their bodies using such technologies and advocate this as an entirely elective procedure.
Some voices such as a Zoltan Istvan has gone as far as advocating chipping as a solution for managing refugees and parents tracking their children.
Mandatory chipping is an established fascist dystopian trope. Whether it's The Borg in Star Trek assimilating an individual against their will or an advanced benevolent civilization with 'health chips',, the technology inevitably becomes used for evil.