To see Kimi Raikkonen back in a Ferrari this year will be fantastic for the Finnish fans, but it will not be easy for him going up against Fernando Alonso.
When I was at McLaren many years ago and a new driver came in, I had an advantage because I knew all the mechanics and the car was tailor-made for me, so I wouldn't give an easy time to a newcomer.
Alonso knows Ferrari very well and has been there for four years; Kimi knows the team from before, but that was many years ago so let's wait and see.