You may just want to check your existing fridge fits in the alcove in your new kitchen.
Whichever it is . . . . . Don’t forget to leave room around the fridge!
Both refrigerators and freezers work by extracting the heat from inside to a radiator coil on the rear of the unit.
If the air flowing past the coils is restricted the efficiency of the refrigerator will drop, and your power bills will go up.
I would recommend a space at least 25mm either side of the cabinet and 40-50mm behind and above the top of the unit.
Don’t then use these spaces to store trays, chopping boards, etc otherwise you are going to block that ventilation path.
I have heard of people installing an external vent behind a fridge mounted on an external wall. . . It seems like a good idea if you remember to shut the vent on hot days. (remember on a 30 + degree day the incoming air will be hotter than the air in the room)
To get drawers out of a Fridge or Freezer you normally have to open the door by much more than 90 degrees. (I have just checked mine and its about 135 degrees)
This means you may need more than the 25mm suggested above on the hinge side unless the front of the fridge projects forward of the alcove.
Built in Fridges
I’m not a big fan of built in fridges, but if you like them make sure that ventilation and door opening are fully considered before you buy.