Identify the missing term in the following letter series.
CFI, FIL, ILO, ?

Let's track the position of each corresponding letter in successive terms:
* First letters: C (+3) $\to$ F (+3) $\to$ I (+3) $\to$ L
* Second letters: F (+3) $\to$ I (+3) $\to$ L (+3) $\to$ O
* Third letters: I (+3) $\to$ L (+3) $\to$ O (+3) $\to$ R

Thus, the next term is LOR.