Advance applications like IoT (Bluetooth, GPS, WIFI)

Bluetooth module:
The small form factor, surface mount module has the complete Bluetooth stack on-board and is controlled via simple ASCII commands over the UART interface. The RN4020 also includes all Bluetooth SIG profiles, as well as MLDP (Microchip Low-energy Data Profile) for custom data.

GPS: A GPS navigation device, GPS receiver, or simply GPS is a device that is capable of receiving information from GPS satellites to calculate the device's geographical position. Using suitable software, the device may display the position on a map along with the directions. The Global Positioning System (GPS) is a global navigation satellite system (GNSS) is a network of a minimum of 24, but currently 30, satellites placed into orbit by the U.S. Department of Defense.

WIFI module:
The ESP8266 WiFi Module is a self-contained SOC with integrated TCP/IP protocol stack that can give any microcontroller access to your WiFi network. The ESP8266 is capable of either hosting an application or offloading all Wi-Fi networking functions from another application processor.