If you think about the description a little bit (never overcomplicate things though) you'll notice that the description sounds like-
"Discord has a bot"
So heading over the Cybsec's Discord server, we find that they have 2 bots in there. One is MEE6 and the other is Dyno.
Dyno has the prefix? and MEE6 has the prefix !.
Let's try asking Dyno for the flag-
Nothing. Now let's try asking MEE6 instead. If you send the message !flag in the server, MEE6 DMs you this-
And we have the flag-
pCTF{1_4m_4_c00l_b0t}
Thank you MEE6. Very cool.