The thing is, at 15 it's not that they don't want to help by nature, but that often they don't see the point or feel like it's being imposed on them without any say in it. At that age they already have their own opinion about everything, so if you just give orders, you're going to clash head-on. Some resistance is normal, yeah, but it's also a chance to change how you're approaching it.
Instead of telling him "you have to wash the dishes," try involving him in deciding how the chores get organized. Ask him what he thinks is fair, what he could do without it feeling like punishment. Some teenagers respond better if they understand it's because we all live in the house and we all get something out of it (a clean space, more free time for other stuff). Another thing that works: let him see the real consequences. If he doesn't wash his clothes, he runs out of clean shirts. It's not cruel, it's just him understanding that things don't appear out of nowhere.
Also consider whether maybe he's overwhelmed with school stuff or other things going on. Sometimes the pushback isn't laziness, it's just that he's got a lot on his mind. And honestly, at 15 they also need some autonomy so they feel like they have control over their life. So adjust your approach, negotiate more than you order, and you'll see that little by little he starts pitching in.