I'm assuming that you are not in a rent controlled area, or you would have mentioned it.
There doesn't appear to be "a" law (statute) addressing unconscionable rent increases. It's a matter of case law.
I found one site (there are many) that provides the following criteria for determining whether a given rent increase is unconscionable:
The actual amount of the rent increase;
The financial circumstances of the landlord (i.e., their revenue, profit, costs, etc.);
How the new rent compares to the rent of other similar units in the general location;
The power dynamic between the tenant and the landlord (how much bargaining power each has); and
Whether the rent increase would surprise or shock a reasonable person.
In searching for case decisions I found 232 appellate case decisions regarding unconscionable rent increases under a variety of circumstances.
https://scholar.google.com/scholar?s...en&as_sdt=4,31
I don't have time to read them all. I'll leave that to you.
A quick glance, however, reveals that the burden of proof is on the tenant and, obviously, you would have to go court to seek relief from the rent increase.

