The word monkey refers to a wide variety of small, tree-dwelling primates. Different species of monkeys have historically lived across Africa, Asia, and South America. In the Fourth World, North America and Europe lacked any species of monkeys, except those brought from other continents for zoos and experimentation. But during the collapse of civilization, as the people who ran those zoos and laboratories abandoned them and let them fall into disrepair, many monkeys escaped and found niches in new bioregions. Later, as tropical jungle spread across more of the world, wild monkeys moved north and south from the equator. One can now find monkeys almost everywhere in the Fifth World.
Some people of the Fifth World have a predator-prey relationship with monkeys, hunting them for their meat. Others, however, do not eat monkeys, either due to religion (Islam and Hinduism) or because of their uncanny similarity to humans.
Because monkeys have such great climbing skills, humans who hunt monkeys must become just as good at climbing. They likely learn the art of tree-climbing from a young age. They may even live in a network of tree houses, linked by rope bridges woven from living vines! Or maybe they live on the ground and have simply mastered climbing high up into the trees. (Perhaps they also specialize in relationship with coconut trees.) They may shoot at monkeys with poison blow-darts, or with bows and arrows.
Another strategy for hunting monkeys would involve an alliance with a local dog pack. Human hunters may work with feral dogs to ambush a pack of monkeys, with the dogs running into the jungle to chase the monkeys toward where the humans wait with bows and arrows. Of course, the human and dog hunters would share the meat afterward. Such a community would likely ally with feral dogs for more hunts than monkeys, and always maintain the friendly relationship that humans and dogs have shared for thousands of years.
A community specializing in relationship with monkeys may live near communities that do not hunt monkeys, creating a distinction between the communities. This both avoids conflict (because they have at least one resource they will not compete over) and potentially creates it (because the community that does not eat monkeys may consider the community that does immoral). The monkey-hunting community may, in response to outside criticism, develop a mythology that justifies its hunting of monkeys. For example, they may believe that deceased ancestors reincarnate as monkeys and give their new bodies willingly to feed their descendants. This explains why monkeys resemble humans so closely, but why eating them does not constitute cannibalism (or at least not unjustified cannibalism).
Since monkeys came to Europe and North America quite recently, humans living on those continents may find themselves less inclined to hunt monkeys than those living on continents where monkeys have always lived. On the other hand, because they came so recently, they may play the role of an invasive species, reproducing too much and too quickly for the fragile new tropical ecosystem to handle. Humans living in areas where monkeys pose that kind of problem may find themselves more inclined to hunt them, to maintain balance and preserve a place in the ecosystem for squirrels and other native tree-climbing mammals that fill similar niches.
Any hunting and gathering community will have to develop traditions that ensure that they do not over-hunt their prey animals, and thus maintain sustainability over the long run. They will almost certainly only hunt larger monkeys, which over time may threaten the population of those larger monkeys, leading to their gradual replacement in the ecosystem by much smaller monkeys, which humans wouldn't bother to hunt. By extension, the trees that those larger monkeys help propagate by eating their fruit may find themselves out-competed by trees favored by smaller monkeys, thus changing the entire ecosystem. So a monkey-hunting community would likely understand the larger implications of their hunts, and take responsibility for maintaining balance in their lands. Such a community may hunt monkeys only during certain times of the year, for instance refraining from hunting monkeys during birth season to avoid hunting nursing mothers. The community's wizard may go into trance and negotiate with the Keeper of the Game to ask how many monkeys they may take that year.