Competitors making similar price adjustments or salary adjustments based on seeing each other's public announcements or sharing data is legal: https://en.wikipedia.org/wiki/Tacit_collusion

That's why it's "legal tacit collusion" when one leading law firm announces salary increases and other law firms immediately match it: https://www.reuters.com/legal/legalindustry/large-law-firms-...

That type of salary matching has been happening for decades.

What's illegal is competitors making agreements with each other to set wages -- via secret emails, etc.