According to the Ashkenazi custom (M.B. 428:26), the Haftarah for this week comes from Yechezkel (22:1-16). For a detailed discussion on the appropriate Haftarah, refer to Levush (493).
This Haftarah is exceptionally rare, having been read only eight times since 1875. The following reading is in 2041. This is because Parshas Acharei Mos and Kedoshim are typically combined, leading to the reading of the Haftarah of Acharei. Even in years when the two parshios are separate, Rosh Chodesh often falls on Shabbos or Sunday, prompting a different Haftarah.
The Levush (493) explains the connection to parshas Kedoshim: Our parsha discusses many obligations and prohibitions we must obey. This Haftorah features Yechezkel's rebuke to the Jewish people for not following many of these commandments mentioned in our parsha.