Google officially dropped support for Mac OS X 10.5.8 (Leopard) many years ago. Modern versions of Google Chrome (versions 90 and above) require modern system libraries and security protocols that simply do not exist in the architecture of OS X 10.5.
The most trusted source for legacy Chrome is (hidden from public navigation) or sites like FileHippo and OldApps . Use this verified URL pattern: Google Chrome Free Download For Mac Os X 10.5.8