Is it permissible to rent an apartment that was previously inhabited by immodest (la'itan) people?

It is permissible to rent the aforementioned apartment, as the default rule is permissibility. The immorality and transgressions that took place within it do not prevent renting it, nor does the tenant incur sin because of it. The sin for those acts rests upon those who committed them, as Allah Almighty says: "And every soul earns not [sin] except against itself, and no bearer of burdens will bear the burden of another."