If it's just block on the inside and outside then most likly that means no insulation.
A picture would be nice to see what you mean by there's cracks. If it's just cracks from where the building settled along a few morter lines that's no big deal, but they should still be cut out with a 4-1/2" right angle grinder and refilled with morter or hydrolic cement or air and bugs can get in.
The best way to add some insulation, make the wall smooth, add a vaper barrier all in one step is to attach strips of plywood cut to about 2" wide and attach then with Tap Con screws. Run the strips at the top and bottom first, then space the others 16" on center vertical. Add 3/4' blue foam between the strips. I did this on the inside and outside of my whole house, as well as replaced all the windows. Heating and cooling cost went from $300.00 a month to $90.00.
All the window and door trim will need to come off, and jam extentions added after the rocks installed.
In the south it's common to see sheetrock directly applyed over block or pored concrete walls but I've never trusted it staying stuck in place, and it adds almost no R value.