The closest equivalent in english would probably be "isn't it?" or "isn't that right?". Its only a semi-question though and is mostly used for inviting someone to agree with you. It can be used in place of です t the end of a sentence. Just replace The す with しょう ^^

As Rayne said, it comes from です and the meanings of it depend on the intonation and on the context. The main use of でしょう are: To express about the future, guess, uncertain things. あした、かれはパーティにくるでしょう。(Tomorrow, he'll come to the party / I think he'll come to the party.) When we recommend something to someone or express our thought with humble feeling It would be better use this word. (この単語を使うほうがいいでしょう。) With the intonation ⤴︎, it's like "....., isn't it / aren't you / don't you?" in English (with expectation of having the same feeling). My puppy is cute, isn't he? (私の犬はかわいいでしょう？) I hope this was helpful.

でしょう／でしょ is an expression that expresses uncertainty or doubts. There are also different ways to use でしょう。 Example: あしたは　あめが　ふる　でしょう - It probably will rain tomorrow つかれた　でしょう。 - Tired, huh? If you have more questions, just ask :3