Data Compression: Strategy, Capacity Planning and Best Practices
TDE encrypts the pages when they are written to disk and decrypts them when they are read from disk into memory. Because data compression (as well as decompression) is performed on in-memory pages, data compression always sees unencrypted data, and hence the effectiveness and efficiency of data compression is not impacted by TDE.
Most other resources I had found only address how TDE messes up backup compression.
