finding human remains is not tracking but a form of air scenting as is drugs and guns.
You have basically three types of tracking
schutzhund which is footstep to footstep and
AKC which is similar but a little looser and probably allows some incorporation of the human scent and
Neither schutzhund or AKC tracking are about finding anything but footsteps and articles left on the track. Both are good foundational work for trailing dogs, though as they teach the dog to work ground odor.
Trailing is following the scent trail depositied by the person which may or may not necessarily be where the footsteps fell but would be close-and variable depending on weather conditions and terrain.
trailing wounded deer, aka, "blood trailing" would be a different discipline - trailing for blood - a dog trained to find a human would be specifically trained NOT to follow any animal - EVER.
Any trailing discipline is a lot of work. AKC and schutzhund are sports but there a folks on the board from Charlteston doing dogpsort. There is also a SAR team there as well SCSD scsearchdogs