@Jojostar
Basically Denji is wanted by the faction created by the Gun Devil for some reason. We don't know why exactly, but Angel hinted there's something important about the chainsaw devil, that devils go to hell when they're killed on earth, and that they go to earth when killed in hell. That while their memories don't remain intact from the experience, it seems the last thing every devil remembers when they die in hell is the sound of a chainsaw. This, along with the ominous dreams Denji is having with the door, implies there's something super significant about the chainsaw devil that would make the Gun Devil badly want Denji.
Anyway, after the first attempt by the Gun Devil to apprehend Denji and the chainsaw devil failed, the Gun Devil sent in the Bomb Devil hybrid(Reze) as a honey trap to try and capture Denji. Only she finds a kindred spirit in Denji's sad and deprived life and so hesitates to finish the job until the very last moment. After which her entire operation goes tits up.
What Reze does manage to do, however, is out Denji on national television. We then quickly find out that apparently Devil hybrids are strategic resources rare and valuable enough that countries are apparently willing to risk international incidents to capture one. Denji is put under guard and we get a wave of would-be assassins/kidnappers come to grab Denji who is put under guard by Japan to try and keep him safe. The ultimate result having concluded last chapter. Presumably after this the MC will go back to collecting bullet fragments to try and hone in on the Gun Drvil. This is the main plot as it's revealed so far.
Now there's a bunch of undercurrents running strong below that plot. The strongest being the enigma of Makima. We know she has some sort of ulterior motive. That the Japan devil hunting branch officials may not be fully cognizant of her abilities up to and including her apparent immortality. We know that Kishibe wants to kill her for some reason. We know that she set up Denji's guards in the international assassin arc to be weak enough to not dissuade organizations from gunning for Denji, but strong enough they don't suspect Denji is a trap. Don't quite remember her reason for this or whether it was even revealed yet. Might be she just wanted to cull the forces of the other organizations with a focus on Quanxi and Santa in particular.