Many sites offering "cracked" software bundle them with trojans, ransomware, or spyware designed to steal personal data, browser passwords, or bank details [1].
Searching for and using "free" registration keys from unverified sources carries several critical dangers: Malware and Ransomware
Trying to get vMix for free is not just about software theft; it's a direct invitation to cybercriminals. The "free keys" and "cracks" you find online are major vectors for malware.