The purpose of this study is to evaluate the safety and effectiveness of an experimental drug called tulisokibart (MK-7240) in people with moderately to severely active Crohn’s disease that has not responded well to treatment. Tulisokibart is an experimental drug with the potential to improve inflammation and fibrosis (thickening or scarring) of the bowel. Researchers will compare tulisokibart to placebo (inactive substance). Study procedures also include physical exams, laboratory tests, colonoscopies, and completion of questionnaires. There are 2 studies in this trial. Study 1 has 4 groups; participants will be randomly assigned to one of these 4 groups. In Study 1, Groups 1, 2, and 3 will receive different doses of tulisokibart, and Group 4 will receive placebo only. Study 2 has 3 groups; participants will be randomly assigned to one of these 3 groups. Group 1 and Group 2 will receive different doses of tulisokibart, and Group 3 will receive placebo only.