You may have heard the term black-hat to refer to a hacker or white-hat to refer to a security consultant, such as a Pentester/Red Teamer. The differences really only vary in intent and outcome.
Hackers:
Their intent is usually for financial gain at your expense. Their outcome is to gain unauthorized access to your network, use it for their benefit, and leave no trace. The breach and all data accessed is covert, and you often do not know they are in your network until it is too late. They have no concern for your data, privacy, availability, or integrity. They have their own interests in mind.
Pentesters/Red Teamer:
Their intent is to uncover the same vulnerabilities and test the same exploits/attack vectors as a hacker, documenting every step taken along the way. Their purpose is to provide you with ample guidance to protect yourself against discovered attack vectors. They go to great lengths to ensure your network/systems remain available and data stays secure and confidential. They provide you with detailed steps to mitigate and/or detect the attack vectors discovered during testing. They set up an out-briefing to go over mitigation steps in person. If Red Teaming, they will test your IR/SOC staff and then hold a debrief with the goal of helping your staff improve. They have your best interest in mind.