Despite what Elliot said, I do think Campbell will be back. It's a negotiation. You always start on the low-end if you're the GM.
By all accounts, Campbell wants to be in Toronto. Looking at the landscape, there are no reasonable UFA goalie options (people are saying Husso, but he's got like a ~25 game sample of being good, it's basically zero sample size for goalies). Fleury probably isn't signing in Toronto, and his night-to-night consistency is also all over the place. Kuemper will be too expensive. There's basically nothing after that.
The trade options (Gibson) are also horrible. Aging and expensive. Hellebuyck is a pipe dream. I mean, maybe you trade for Varlamov. but that is the only other decent and relatively affordable option.
I think they end up settling on a 3-4 year deal between $3-3.5 million with Campbell. The Leafs can't afford to allocate more to goaltending anyway. He wasn't the reason they lost the series.