CAN FD replaces CAN bus
CAN FD (Controller Area Network Flexible Data-Rate) is a data-communication protocol used for broadcasting sensor data and control information on 2 wire interconnections between different parts of electronic instrumentation and control system. This protocol is used in modern high performance vehicles.
CAN FD is an extension to the original CAN bus protocol that was specified in ISO 11898-1. The basic idea to overclock part of the frame and to oversize the payload dates back to 1999. Developed in 2011 and released in 2012 by Bosch, CAN FD was developed to meet the need to increase the data transfer rate up to 5 times faster and with larger frame/message sizes for use in modern automotive Electronic Control Units (ECUs). 
As in the classic CAN, CAN FD protocol is designed to reliably transmit and receive sensor data, control commands and to detect data errors between electronic sensor devices, controllers and microcontrollers. Although CAN FD was primarily designed for use in high performance vehicle ECUs, the pervasiveness of classic CAN in the different industries will lead into inclusion of this improved data-communication protocol in a variety of other applications as well, such as in electronic systems used in robotics, defense, industrial automation, underwater vehicles, medical equipment, avionics, down-hole drilling sensors, etc.