It was powerhouse Louis Vuitton that kicked off the streetwear-crossover obsession with its hugely successful collab with skate brand Supreme. Then there was the incredibly well-marketed tie-in between buttoned-up Ralph Lauren and cult label Palace, whose sweaters and brightly patterned pajamas sold out in minutes last winter, as well as, earlier this year, 120-year-old luggage brand Rimowa’s dreamy line of roll-aboards with L.A.-based mixed-media artist Alex Israel. Meanwhile, the collaboration between Brit punk maven Vivienne Westwood and sports champ Asics landed in April. This mash-up of off-duty cool and old-school fashion heritage isn’t slowing down anytime soon. Even Paris’s Champs-Élysées, ground zero for luxury brands, is catching on. Alongside the avenue’s Chanels and Diors, France’s first hip-hop-inspired streetwear label, Homecore, is selling its sneakers and beanies inside a rainbow-colored pop-up through June. Now that hip-hop-skater cool has gone big on the boulevards, high-fashion labels will no doubt be on the lookout for fresh fodder.