No one can say for sure, as ODST isn't out yet, but I wouldn't count on it. Seeing as it was cut from the original game, there's a chance it may show, like the machine gun turrets. However, ODST is going to be more of a tactical shooter. You don't have sheilds or as much health, so charging into a crowd of enemies with a blade wouldn't be a good idea. i belive "knifing" has worked ver well for call of duty in wich case you wouldnt charge an enemy but given a chance to slit an elite throat or 2 i would. xLEFTHAND0FG0Dx...."Spartans never die... if only that were true."
However there is a chance you could use it how Sgt. Forge used it in Halo Wars or if you want to sneak up on one enemy and stab him in the back. An ODST probably does not have the superpowered strength of SPARTAN-IIs; therefore, it is quite possible that the combat knife can be used as a melee attack. A number of games have knifing, not just Call of Duty, so this would not be too much of an imitation.