Just Adopted a Four Year Old Mixed Breed German Shorthaired Pointer Rescue

I just adopted a four year old mixed breed German shorthaired pointer (or I assume him to be one because he looks like one - see attached picture). He came from Tennessee. I tend to think that maybe he was used as a hunting dog but he was too meek and mild so he was let go just based upon his temperament and behavior.

Can anyone give me some tips for these guys? Any sort of things I should look out for? Any health issues that may occur? Any information is appreciated.