They are essentially the same game. The game is called Clue in the North America, and Cluedo in much of the rest of the world.

There are a few superficial differences:

The murder victim is "Mr. Boddy" in Clue and "Dr. Black" in Cluedo.

"Miss Scarlet" in Clue is "Miss Scarlett" in Cluedo.

The "wrench" in Clue is the "spanner" in Cluedo.

"Miss Scarlet" in Clue is "Miss Scarlett" in Cluedo.

The word "Cluedo" is thought to be a combination of the words "clue" and "ludo". Ludo is a traditional board game in which the players race their gamepieces around the board according to rolls of dice (well-known commercial versions of the game include "Aggravation", "Trouble", and "Parcheesi"). "Clue" has a "mystery" connotation, so combining the two words you end up with "mystery board game": Cluedo.

"Clue" is known as "Detetive" in Brazil and "Quien" in some Central American countries.