Step 1: Observe the first letters.
\[
C,E,G,I,K,M,O,Q,S
\]
The first letters should increase by 2 positions each time.
Step 2: Observe the second letters.
\[
Z,Y,X,W,V,U,T
\]
The second letters decrease by 1 position successively.
Step 3: Find the mismatch.
After IW, the next term should be KV, not MV.
Therefore, MV breaks the pattern.
\[
\boxed{MV}
\]