This is the 124th most frequent Italian word.
ci
The Italian word "ci" means "us," "there," or "it," depending on context, and can also be a reflexive or reciprocal pronoun.
In this sentence, 'ci' is used reflexively, meaning 'ourselves,' implicating that the speaker is including themselves in the action of seeing each other.
Ci vediamo domani!
See you tomorrow!
Here, 'ci' is part of the expression 'ci sono,' which translates as 'there are,' and it serves to introduce the existence of something.
Non ci sono problemi.
There are no problems.
In this context, 'ci' stands as a pronoun, replacing an implicit object preceded by 'about,' indicating the object of thought.