Wage is a drug lord in Night City. Case owes Wage money, and according to lying Linda Lee, Wage wants our guy him dead. After a brief stand off in the Chat, Case and Wage work out the misunderstanding, and Case pays off his debt to Wage in chapter 2.
Julius Deane runs and import and export business in Night City. Case originally goes to him for information as to whether Wage really wants him dead. Deane probably ordered Linda Lee to be killed, although it's unknown whether he acted on his own or under orders from Wintermute.
Zone is a pimp that runs his game on Ninsei Street. We only see Zone once as Case briefly runs into him at the Chat bar. His nonchalance over Case's cobra knife suggests that he is well acquainted with violence.
Between the three, we get a good sense of the type of person who thrives in Chiba City. Lonny doesn't bat an eye when he sees Case lugging around a dangerous weapon, Wage couldn't care less when he has a gun pointed at him, and Deane puts business before all other considerations, including Case's and Linda's lives. By seeing how Case interacts with these guys, we also get the sense that Case doesn't have what it takes to truly be a Night City hustler. He's from a different stock, though that's certainly not a bad thing.
P.S. It's also worth noting that Wintermute sometimes takes on Deane and Zone's appearances while communicating with Case.