There are certainly many undiscovered species out there right now. But a 8 foot bipedal primate is not one of them. It's just not possible. For one, primates have only flourished in jungle environments with lots of rain. They are for the most part herbivores. It's been that way for millions of years, supported by fossil evidence. Meanwhile there is zero evidence of a stinky 8 foot hermit beast living in North America. It cannot provide a primate herbivore diet. No primate fossils have ever been found in North America. No hair or DNA evidence of any kind. Are we to believe that these beasts live solitary lives, yet never accidentally die leaving remains? There are thousands of men and women that spend their entire careers out in the wilderness, as well as cameras recording the areas of supposed Sasquatch territory. Millions of game hunters out there, many using trailcams. Some idiots make a full time career out of Bigfoot hunting. Yet nothing but stories.
It's just not possible for a primate to escape discovery unless we're talking about extreme environmental isolation. Which excludes North America.