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.