I have seen that when I had enrolled for the CC course. There was two Courses alloted to me after registering. They were basically named as CC Cybersecurity course and another one which was named as CC Cybersecurity 1M. What does the 1M stands for? I thought of it as a 1 month course and tried to complete it first. But it stayed longer than that. Thereof I'm a little confused regarding this instance.
I can see the confusion....
1M == 1 minute
1M == 1 month
1M == 1 meter
1M == 1 male
1M == 1 million
IM == 1999 in Roman numbers (close, but not the same)
In this case, I think Early_Adopter has it right. Probably a reference to ISC2's program ("ISC2 Pledges One Million FREE ISC2 Certified in Cybersecurity Courses and Exams"). 1MCC appears in the link to that page.
One Million
1999 = MCMXCIX
IM would be 999 if that syntax were legit (which it wasn't)