C-3PO and R2-D2 are both iconic characters from the Star Wars universe.
Both characters, or rather, the two robots, have their own unique personalities and abilities, and have played important roles in the Star Wars saga.
C-3PO is a protocol droid designed to interact with humans and carry out tasks related to etiquette and protocol, while R2-D2 is an astromech droid, counterpart and friend of C-3PO.