Got it.

So RBF and CPFP are both fee-bumping techniques. They can be useful when your transaction gets stuck in the mempool for too long.

RBF = Replace-by-fee CPFP = Child-pays-for-parent

RBF can be used to fee-bump outgoing transactions, while CPFP can be used to fee-bump both incoming and outgoing transactions.

Here is a great introduction article from Bitcoin Optech: https://bitcoinops.org/en/scaling/fee-bumping/