The purpose of this research study is to see how well BMS-986165 (the study drug) works and how safe it is in patients with moderate to severe Crohn’s Disease (CD). The duration of study participation is approximately 112 weeks (785 days) in 5 periods, as follows:

1. Screening Period: up to 4 weeks (28 days)
2. Induction Period: 12 weeks (84 days)
3. Maintenance Period: 40 weeks (280 days)
4. Open-label Extension Period: 52 weeks (364 days)
5. Post Treatment Follow-up Period: 4 weeks (28 days) In this study, you will be assigned to a group to receive either BMS-986165 (study drug) or placebo (no drug). The chances of you receiving BMS-986165 are 3 in 4 (75%).

Approximately 240 participants (men and women ages 18 to 75 years) will participate in this research study.

Inclusion Criteria:

• Documented diagnosis of Crohn's Disease (CD) for at least 3 months prior to screening, including ileal, colonic, or ileo-colonic disease distribution
• Must have had an inadequate response, loss of response, or intolerance to 1 or more of the standard treatments
• Must have active moderate to severe CD
• Men and women must agree to follow specific methods of contraception, if applicable

Exclusion Criteria:

• Severe or fulminant colitis that is likely to require surgery or hospitalization
• Presence of a diagnosis of alternative forms of colitis (infectious, inflammatory including ulcerative colitis, malignant, toxic, indeterminate, etc.) other than Crohn's Disease
• Previous exposure to BMS-986165 in any study
• Any major illness/condition or evidence of an unstable clinical condition (eg, renal, hepatic, hematologic, gastrointestinal, endocrine, pulmonary, immunologic, psychiatric, or local active infection/infectious illness) that, in the investigator's judgment, will substantially increase the risk to the participant