For completeness, let's consider all the possible cases:

       unsigned char global_variable;
static unsigned char static_global_variable;

void func( void )
{
          unsigned char local_variable;
   static unsigned char static_local_variable;

   :
   :

   {
             unsigned char inner_local_variable;
      static unsigned char static_inner_local_variable;
   }
   
}

global_variable, static_global_variable, static_local_variable, and static_inner_local_variable all exist permanently in memory, so they will retain their contents until specifically modified - the difference is in accessibility:

global_variable can be accessed by anything throughout the entire system - including functions in other souurce files (it has global scope);

static_global_variable can be accessed only within the current source file (if has file scope);

static_local_variable can be accessed only within the function func;

static_inner_local_variable can be accessed only within its inner block within the function func.

local_variable only exists within the function func - its memory may be re-used outside that function and, therefore, it will not retain its value between calls to func.

inner_local_variable only exist within the inner block inside function func - its memory may be re-used outside that block and, therefore, it will not retain its value outside that block (and certainly not between calls to func).