Retaliation in the workplace is real. Each time I give a training, several people come up to me to talk about their experience with speaking up... and the seemingly inevitable retaliation. This is the typical story. Your supervisor hasn't been treating you fairly/professionally/respectfully. At first, you let it go, "Maybe it's just the stress of this project." you think. But the behavior gets worse and the treatment at last month's staff meeting was the straw that broke the camel's back.
You decide you have to say something, but how? and when? Over the next two days, you meet with several co-workers to figure out the best strategy. How to be calm and firm. How to set boundaries and expectations. You finally "pop into" their office to have the chat. You brought your A game, and your supervisor appears to be listening, but gets cold, then defensive. The meeting ends with both of you ostensibly hopeful that things will get better.
The next day, they avoid you. Days later, you realize you're frozen out. Whether intentional ("I can't believe that employee had the gall to say that.") or unintentional ("I can't believe I acted that way, I'm so embarrassed that I can't even look at that person.), you experience it as retaliation.
You aren't alone. Check out this Forbes article, "The 12 Most Common Retaliation Tactics."