What in these totally different books is there, that obvious?

Yes.

Running.

Forest.

And what else is there?

Chapter three, Fire And Ice

Chapter One, The Hunt

The female is running in both books.

Stephanie, the authors doesn't mention who exactly is running after the main character/protagonist.

Oh, but Shadow, in Fire And Ice is running from love.

And the protagonist in The Hunt is running from him in general.

And the main killer dedicated his life to ruining Stephanie's. Hayden is trying to find Shadow or so it seems...