Red and blue lines on the map in Fortnite, what do they mean and how to use them?

How to make good use of and what do the new blue and red lines mean on the map in Fortnite?
The new Chapter 3 Season 2 has just begun. Doctor Slone and IO reappeared on the island, who disappeared in Chapter 3 of Season 1. Along with many interesting novelties, red and blue lines have been added to the game.
However, not everyone knows that they can be used. The lines mark the territories of the two factions, but they can make it easy for some to win.
Red lines
In the beginning, it is worth explaining what exactly the lines mean. The red “zones” are those taken over by the IO. While exploring these places can be dangerous due to the aggressive NPCs, it can often be beneficial. In these areas, the player will find many armored UR vehicles scattered around the area. In addition, there are airships moored high in the sky. You can get to them with zip lines and look around the area, which makes it easier to look for loot. There is also a powerful IO weapon that can be put to good use for a Victory Royale.
Be careful when you are in these areas. Each NPC you meet will automatically attack the player.
Blue lines
As for the areas covered by the blue line, they are definitely friendlier. It is there that there is a Rebellion that is friendly towards the player. You can find armored combat buses and NPCs willing to trade there.
The problem is their location on the map. The blue lines are mainly located on the outskirts of the island, which means that sooner or later they will be swallowed up by the storm. This forces the player to enter enemy red territory. At the moment, it is not known what the plot meaning of these lines are. However, the community suggests that a great battle may be brewing on the map.