Many businesses expect one employee or a small MSP to be able to manage the complexity of IT networks, industry regulations, cloud computing, system requirements, cybersecurity, application updates, VOIP, software licenses, hardware repairs/replacements, and more. This is a lot to expect, especially if you have a one person IT department.  Co-managed services add to the services of an internal IT team or other MSP by having the support and comprehensive knowledge of another managed service provider who may specialize in certain aspects such as cyber security or the management of special projects.  They also may just be there to lend an extra set of hands to an already overwhelmed IT staff.