Style is more than anything else, it is an expression of personal choice
The Cosmic Era has created a veritable windfall of new materials, ranging from utilitarian to the unimaginable, and the world of fashion is not going to leave all of those things laying on the table to stick with age old materials. The new is drug in, and the old is never quite put out to pasture. Leather and lace will never go out of style, even if the leather is synthetic, and the lace is made of harmonic LED crystals, likewise, there are going to be hypertech gadgets that stick with a leather case when polymers are available, and in the Cosmic Era, denim is ageless.
There is a joke that time travel was invented somewhere around the end of the 18th century because in large part gentlemen's fashion hasn't changed since then. While there have been changes to the trim and cut, the formal suit remains largely intact in the cosmic era, matching suit pants, undershirt, coat, and tie. The rest, cummerbunds, suspenders, vests, and the rest cycle through being hot, being retro, retro hot, or the next iteration of fashion.
One of the sins of a suit is sweat. The new thermoablative fabrics, pioneered for spacesuits and fire protection, have made their way into men's shirts and undergarments, allowing them to shed heat and stay cool no matter how heavy the suit and how hot the environment. This is a bit of exaggeration, as the garments offer no actual protection, but allow you to shed heat. This keeps you cool and focused in the board room, at the business luncheon, or even calm and collected when questioned by authority.
Made from the same memory materials as an encounter suit, armure suits can offer a fair degree of ballistic and impact protection. This material is typically reserved for stylish vests, overcoats, and other such garments. This is a popular upgrade in professional suits as the armor protection is much less important than the demonstrated style and status consciousness of the material.
A hot commodity, these elastomers are the cutting edge in suit style and design. With minor adjustment, the suit can automatically fit itself to it's wearer, relaxing or tensing where it needs to to get that perfect fit. The color changing ability of the polymers means that the suit can likewise change colors. This isn't the peacock and parrot hypercoloring of street clothing and mutattoos, but a preset range of cool, stylish, and sophisticated colors, and even patterns.
The Armure style suit can offer a decent degree of protection for the well heeled socialite, as well as being innocuous and stylish. The level of protection offered is comparable to modern police body armor, and the suit can stop most small caliber, low velocity rounds with ease, while being defeated by higher powered military gear. In the Cosmic Era, this renders most wearers protected from civilian grade firearms, shrapnel, and the injuries that might be sustained in an assault.
The Greatcoat - stylish, commanding, impressive, all words that describe the classic greatcoat. Worn over a suit, the greatcoat is large garment that has a lot to work with. Modern styling in greatcoats is favoring early to mid 20th century European flair (dictator chic) with angular cuts, woollen blends, and imperial couture. The advantages of the current greatcoat is that the garment can be reinforced to stop even sniper rounds, allowing for safety as well as style on the heloport, concourse, or promenade. The greatcoat makes use of a cascading dragonscale of SLAB medallions. Sandwiched between two layers of reflexokinetic material, the coat is able to stop the vast majority of available non-magnetic, non high energy weapons.
The Undervest - a popular undergarment, the undervest can provide a splash of color or pattern to set off a subtle or somber suit. The vest is also easily reinforceable, having a different pattern, but similar construction of SLAB inserts. This can provide adequate protection without relying on a greatcoat, as well as demonstrating impeccable fashion sense.
The Cummerbund - the form fixing cummerbund switches in and out with the vest in popularity, but enjoys a different set of modifications. The cummerbund is designed to protect their wearer from knife wounds and the dreaded muffin top. As such, the material is strong, and has a banded construction. Anything that strikes it with sufficient force will cause the reflexokinetic material to stiffen, but the bands do so at deliberately different speeds and tensions, with the end effect being the knife or other weapon being flung from the assailant's hand, or should they keep a hold of it, the end being broken.
Cufflinks, Tie Pins, and other Accouterments - These small items can serve a variety of safety, utility, and protective roles in addition to their main use, looking impeccable. Frequently having metal housings and the ability to hold micro-sized devices the imagination is often to limit to this area of fashion.
Micro-explosives: not the sort for exploding a room full of radicals, but certainly enough to break a set of handcuffs, bust a locked door, or deliver a cloud of smoke to cover a quick retreat, or deliver a dose of chemical agent. The use of these types of augmentations are regulated, with the most common used models containing capsules of pheromones or repellent/stink bomb agents.
LEDs - equipped with micro batteries and LEDs, the accouterments are luminescent fashion. It is also very easy to have a tracking device/panic button embedded in a cufflink or tie pin. Should a VIP be accosted, a quick squeeze of the device alerts law enforcement, security corp agents, or bodyguards that the wearer is in distress.
How often in entertainment and video games does the boss fight come down to fighting a guy in a suit. Actual self defense experts will tell you suits are terrible to fight in, they restrict your freedom of movement, and something like a tie is literally a rope tied around your neck for someone to grab and pull into a submission/knock out in a fight. That being said, the armure suits are still terrible to fight in, but the men wearing them aren't engaging in fisticuffs, they are pulling guns and shooting back, wearing the suits like civilian body armor so that they aren't injured in a gun fight. This is going to be enjoyed as high fashion by the wealthy and elite, and seldom used for anything but that in the highest circles, much like high end SUVs that never go anywhere other than suburban shopping and parking lots. On the more versatile end, shadowrunners, fixers, underworld bosses, and those who have access to money, but still remain in the real of potential injury, will wear and use the lower end versions.
Stylish body armor to keep bosses, dandies, would be James Bond's, and other less reputable sorts on their feet when the bullets and punches start flying.