Use existing room decorations. If there are posters or other artworks on the wall,
you can route the loudspeaker cable to the back of the surrounding
loudspeakers
Use a cable clip with integrated nails to secure the loudspeaker cable to the floor of the room. In this case, the cables are not completely invisible, but they are completely unobstructed. If there is a wall-to-wall carpet in the room, you can plug the cable between the carpet and the baseboard, so that they are more or less invisible.
Use light bands. If you have light strips in your room, you can route black speaker cables beside them to make them completely unobtrusive.
Lay the cable on the carpet of the room or even under the carpet. Flat cables are best suited for this situation.
Stick the loudspeaker lead to the wall. You can paint it in any color so that it is basically invisible.
Use painted conduit or conduit. Several companies produce long cable ducts, conduits, and cable ducts, hiding cables in hollow structures along the corners of the floor or wall intersections. They can even surround the loudspeakers along the middle of the wall, and you can paint them to match the color of the wall. But the line around the black loudspeaker needs you to spend more time hiding it.
Hide loudspeaker cables and wires on the wall. In order to achieve the ultimate cable stealth effect, you can lay loudspeakers and other cables on the room wall. You can even install wall panels with terminals next to loudspeakers and other devices for various types of connections. Of course, this requires a lot of work. Unless you are a serious DIY person, you'd better hire a professional installer to do it.