The song "MCMILLER" by Rehab x Ansi talks about not being like Mac Miller, who tragically passed away from a drug overdose. The artists emphasize that they won't let themselves be killed by a drug dealer and they don't brag about dealing drugs. They talk about their own experiences with drugs and the gritty lifestyle they live, with references to dealing and using drugs like weed. They also express their loyalty to their crew and their determination to succeed in life despite the challenges they face. Overall, the song is about the struggles and temptations of living in a tough neighborhood and trying to make it out while staying true to themselves.