The inclusion of cumin can provide that underlay of lived-in quality that is can be so elegant and old-money in fragrance compositions that would be effete without it: Eau d'Hermès by Edmond Roudnitska for Hermès is a great example, a citrus-leathery cologne for men (that women can share) which feels like a worn pair of chinos for a walk outdoors. Roudnitska's talented pupil and modern maestro of niche, Jean Claude Ellena, took this segment off the old into creating his masterful Cartier Declaration: the cumin in tandem with cardamom creates a contrast of cool and warm, on a mossy, foresty base that feels fresh, yet providing the feeling of someone who is breathing, feating and living underneath (and probably has apocrine glands that function properly and freely!), not a sterilized version of a human just out of the sauna. In Diorella, another Roudnitska classic, the ripe melon, almost garbage-like note marries well to the dirty, spicy cumin to make the refreshing top notes less acidic and more enigmatic.
To extend this notion, cumin can also provide a sexy glimpse, as in afterglow bodies which although were clean to begin with now bear the fruits of some romping around. The inclusion of cumin in the modernized Rochas Femme was an especially enlightened idea in view of that aspect; although purists argue it's quite different than the original Roudnitska creation, one can't fail to notice that at least in spirit, if not in letter, it stays close to the dicta of the grand master. Absolue pour le Soir by Maison Francis Kurkdjian marries cumin and powerful musky notes to render a very naughty olfactory experience indeed! Even though it is profoundly sexy, however, the fragrance never veers into the territory of vulgar, not meaning to please everyone via "easy" popular tricks. In Parfum d'Empire Aziyadé the cumin inclusion provides the exotic touch, but also the languor of the harem, the name deriving from the story of a concubine in Ottoman Turkey. In Jubilation 25 (Amouage) cumin plays a significant role into providing the decadent fruity chypre ambience of classics of yore. Fleurs d'Oranger by Lutens, although certainly not a lonely case of cumin use in the vast portfolio of spicy wonders in the line, is probably the most erotic floral of the brand; lush, dense, seriously romantic, fanning the spice over the carnality of orange blossom absolute and dense, clotted tuberose essence. A play of seduction in the cloistered gardens of Cordoba.
Other times the author of a perfume is interested neither in the lived-in elegance, nor the sexiness, but in providing an unexpected touch that will distinguish the composition into an unusual spicy arpeggio above the clichés of cinnamon and pepper: Kenzo Jungle L'Eléphant was such a case, as was L'Autre by Diptyque, their distinctiveness probably the very reason of their market demise...
WEARER'S CAVEAT EMPTOR
Cumin being the great divider it is, however -several people find a prominent note of cumin either too foody (like Indian food, where cumin is featured in the preparation of curry mixes) or too "dirty" (as in body odor)- sampling is definitely recommended for any fragrance that features cumin prominently. This is a matter of cerebral familiarity with it rather than skin compatibility which goes both ways: If you know the spice, you can pick it up and be indifferent to it due to over-familiarization through spicy food, or alternatively you can pick it up better than someone non familiar with it and thus be more attentive to it, especially if you don't fancy Indian or Middle Eastern food, feeling it sticks out like a sore thumb!)
Cumin has been inumerable times linked to the scent of sweat on online fora and communities, to the point that it is enough to even mention the list of notes featuring it to have at least one person wondering whether the perfume will end up smelling like stale sweat on them... It's an anecdote, but a good one; when Kingdom by Alexander McQueen, a cumin-laced skanfest by all accounts, launched, an experienced online member by the alias Serpent, described his impression of the new fragrance in the shocking but funny imagery of a "hooker eating a burrito". Such was the effect of the cumin overload!
With cumin, you have to be very deliberate, it seems.
Related reading on PerfumeShrine: Cumin as a raw material, pheromones, sweat and list of cumin-laced fragrances