While pursuing legal action against individual downloaders is rare, using cracked software or stolen keys violates the Digital Millennium Copyright Act (DMCA) and the Terms of Service of distribution platforms like Steam. Your account could be permanently banned, and in some jurisdictions, you could face fines.
Do not fall for it. The only people profiting from those videos are the scammers behind the affiliate links and malware payloads. cities skylines license key.txt