Conditional format. Date - Date<>deadline = red or green

is that 2 working days ?
or any 2 days

as E2 should be later than C2 - then E2 - C2 , otherwise C2-E2 will give an errors as c2 is less than E2 and so you get minus dates - which excel wont like

And( (E2-C2)<2 , E2<> "")
=AND((E2-C2)<2,E2<>"")

What happens if exactly 2 days ?

=AND((E2-C2)>2,E2<>"")

Also if you want to highlight the C column and the E column

then you will need $ to fix the columns

=AND(($E2-$C2)<2,$E2<>"")

=AND(($E2-$C2)>2,$E2<>"")