Limitations in Microsoft Teams:

Function Maximum limit  
The number of teams the user can create Subject to a limit of 250 objects  
The number of teams the user can belong to 1000  
Number of team members 10,000  
Number of owners per team 100  
Number of organization-wide teams allowed on a lease 5  
Number of team members covering the entire organization 5000  
Number of teams a global administrator can create 500,000  
The number of teams a Microsoft 365 or Office 365 organization can have 500,000  
Number of channels per team 200 (including deleted channels)  
Number of private channels per team thirty (includes deleted channels)
Number of private channel members 250  
Maximum number of members in a group Office 365 that can be converted to a team of 10.000  
Post size in a channel conversation Approximately 28 KB per post  

For more information on the restrictions, please visit the Microsoft website: https://docs.microsoft.com/pl-pl/microsoftteams/limits-specifications-teams