If you mean A Path Beyond (C&C Renegade) then yes its a full Total Conversion Mod FPS using C&C Renegade.
There are a good few differences between the 2 though;
APB is based in the Red Alert C&C series, just after the Retaliation and Aftermath games.
There is a multitude of different buildings that are used in a verity of different set ups showing the difference in "tech" levels
APB has extremely big maps compared to the standard Renegade.
Its still in the Beta phase but its a good enough game to play now. the guys are doing a good job of geting the feel right and accurate to the RA universe.
It is also totally free to download and play
ermmm that all i can think of at the minute