This is a Phase IIb, randomized, placebo-controlled, double-blind, parallel-group 24-week study to assess the efficacy, safety and tolerability of three doses of AZD8965 versus placebo administered to participants with IPF. The enrolled participants will include those on stable dose(s) of one or two approved antifibrotic therapies and those who are not taking any antifibrotic therapy. Approximately 360 participants will be randomized across approximately 200 sites globally.