As a transcription regulatory factor, IER2 plays an important role in various cellular responses and can impact the invasive behavior of tumors.[16, 17] Studies have pointed out that CAF regulates the biological behavior of tumor cells mainly through paracrine signaling.[24] To probe the downstream mechanism behind ERS‐CAF's promotion of chordoma progression, we collected supernatants of CAF before and after IER2 knockdown for data‐independent acquisition proteomics analysis. Here, IER2 is linked to chordoma.