I can confirm that the TSS-normalized RPK values from HUMAnN are equivalent to TPM values. We avoid saying “TPM” since we are often quantifying at the DNA level (and the “T” in TPM refers to transcripts). HUMAnN’s term for this unit is CPM or CoPM, indicating generic Copies Per Million (not to be confused with Counts Per Million, which would indicate an absence of adjustment for sequence length).