Allston pokes into Cambridge. Cambridge surrounds Allston. West of Cambridge is Arlington, Watertown or Belmont. Southwest of Cambridge is still Watertown.

As for Bunker Hill, Somerville is North-East of Cambridge. Only a tiny slice of Cambridge connects to Bunker Hill. The rest of the North-East border is all Somerville.

Boston is South-West of Cambridge, that's the real story. It surrounds part of it on 1 side in one area because the Charles river curls around Cambridgeport, then it curls the other way and Cambridge surrounds part of Allston.