Here's data that I attempted to get and translate from the site itself (all added information is just my suggested understanding or for labeling purposes):
If we work together, there is no impossibility.
This new feature allows a special buff to be activated if you assemble your MCC team with a specific set of characters. Each MCC Buff is different and powerful as it is applied.
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Town Soldier Team
Buff: Attack class (ATK Rating) +1, defense class (DEF Rating) +1
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Love Triangle
Buff: Attack power (ATK) +5, attack speed +10%, defensive power (DEF) +20
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Sharpshooters
Buff: On-target hit ratio (Accuracy?) +10%, attack speed +5%, penetration +5
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Martial Artists
Buff: HP+1000, defensive power (DEF) +5, defense class (DEF Rating) +1
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Ustiur Rescue Knights
Buff: Drift speed (Movement Speed?) +10%, state abnormal resistance +10
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2 Boys and a girl/Kids Team
Buff: Defense class (DEF Rating) +1, HP+2000
These are the six MCC buffs that version 3.1.0 has to offer. More may be coming soon, so keep your eyes peeled!