The Tactical Campaign features 12 Roles additional to those presented in the (Starfleet) core rules. As far as I can see, only the “Tactical Officer” is entirely new. The other Roles are taken from the Command Division (1) and Operations Division (6) supplements, and the Player’s Guide (4). These sources though only present brief descriptions and the Role’s crunch, i.e. the Role Affect, resulting in short paragraphs per Role.
The Tactical Campaign expands each description to half page writeups, featuring more fluff and quick-building advice. Some Roles are slightly rewritten, mechanically, though this might be a result of the new presentation and no change might be intended.
Edit: @Modiphius-Jim Any chance, typos can still be corrected for printing? If so, check whether the Saurian Lieutenant on p. 40 is called Dillon or Dillion. 