Why every single time I star play this MOT, I will be infomed Mike and Trevor will be pursued once they enter the city central, then some killer which is the red point will chase Mike.

 Prob you are between mission (Caida Libre - if I'm correct*) that start this script and another mission (Derailed*) that stops it. 

Edited February 14, 20242 yr by Kate.Denson

Either continue playing the sorry or install a gameconfig that already has 100% of the missions done.

4 hours ago, Lennyy said:

Either continue playing the sorry or install a gameconfig that already has 100% of the missions done.

but if I dont have 100% missions done, what else I can do, thank you

1 hour ago, XNJR said:

but if I dont have 100% missions done, what else I can do, thank you

I described both your options in my initial response. Either continue playing the story until you are no longer being followed or install a 100% game save. 

A third option would be to revert back to an earlier save where you aren’t followed yet. But having a safe of that point is pretty rare as most people only have one save to begin with.