In my province the cap for increase was usually around 1.5 - 2% for existing tenants/renewing lease.
The conservative gov went ahead and fucked everything up and said this doesn’t apply to anything built after 2005, or new builds - that means any new anything in an existing building.
New basement rooms? No cap. (No cap) But, if the basement had rooms 35 years ago, and you ‘build’ “new” rooms, it isn’t new and falls under the older more tenant friendly laws.
However, between tenants, a landlord can do whatever the fuck they want to prices.