I have never investigated this topic but I it seems like reduction of nitrile group in CF3CN is possible. Following articles can shed some light on this topic:

http://www.sciencedirect.com/science/article/pii/S0022113900836878

and

http://www.sciencedirect.com/science/article/pii/S0022113900829899

http://www.sciencedirect.com/science/article/pii/S0040402014003500

http://pubs.acs.org/doi/abs/10.1021/jo048682m

Please clarify your question.

Ajay

You wrote

is CF3 group prevent reduction of nitrile group?

The answer is No

You can reduce the nitrile group in the presence of CF3 group, e.g.

---  Goble, Stephen D. et al  PCT Int. Appl., 2005067502, 28 Jul 2005

To a solution of 4-trifluoromethyl phenyl acetonitrile (40 g, 215 mmol) in 2N NH3/MeOH (400 mL) was added Raney Ni (~4.0 g). The reaction mixture was placed in a par-shaker and shook under 50 Lb pressure overnight. The solution was filtered through celite and concentrated in vacuo to yield the desired amine (38 g, 95% !!!!!)

Good luck