When non-renewal is disguised retaliation
It depends on the circumstances, but a refusal to renew that is motivated by your exercise of a protected right can raise a retaliation concern. Landlords cannot use non-renewal as a disguised way to punish tenants for asserting their rights.
While landlords often have discretion around renewals, that discretion is not a free pass to retaliate. If a landlord declines to renew soon after you complained about conditions, reported a violation, or otherwise exercised a right, the timing and motive can point to unlawful retaliation, and other protections — such as local "just cause" eviction rules where they apply — may also come into play.
Local rules matter here, because some cities limit a landlord's ability to end a tenancy without a valid reason, which can affect non-renewal situations.
So the questions are why the landlord refused to renew and when, relative to your protected activity. If your landlord declined to renew your lease shortly after you asserted your rights, a free, confidential review can help you understand whether it may be retaliatory and what protections apply where you live.
This is general information about California tenant rights, not legal advice. Every situation is different.