The Haftarah of Emor, from Yechezkel, describes the role of the Cohanim and the additional commandments that apply only to them.
Linear annotated translation of the Haftarah of Emor
The source in the Torah for those commandments is the Parsha, Parshat Emor.
It is so obvious what the connection between the Haftarah and the Parsha must be that it actually makes it difficult to say anything meaningful about it. True, one could discuss the differences in the details of the commandments in the Torah vs. those presented by the prophet Yechezkel, but interesting though that may be, it does not in fact shed any light on the Parsha itself.
But this does: Sanctity and Continuity