Any alternative premedication regimen must be discussed with, and approved by the BMS Medical Monitor/Study Director prior to administration of any study treatment. Medical management of any infusion reactions occurring irrespective of whether premedication was administered, r emain at the discretion of the investigator. Guidelines for management of infusion reactions are described in Section 7.3.6 . 7.1.1 Method of Treatment Assignment This is an open-label study. All participants mu st be assigned a part icipant number upon providing signed written i nformed consent. Based on the r ate of participant e nrollment, the Sponsor will implement an IRT to assign participant numbers, study treatment group, and dose level, as well as manage drug supply. During the screening visit, the investigative site will register the participant by an IRT designated by BMS for assignment of a 5-digit participant number that will be unique across all sites. E nrolled participants, including those not dosed, w ill be assigned sequent ial participant numbers . Revised Protocol No.: 04 Date: 31-May-2019 83 Approved 5.0 v Approved 1.0 v Clinical Protocol CA021002 BMS-986226 anti-ICOS The participant identification number (PID) will ul timately be composed of the site number and participant number. For example, the first pa rticipant screened (e.g., enrolled) at site number 1, will have a PID . Specific instructions for using the IRT will be provided to the investigational sites in a separate instruction manual. Once it is determined that the participant meets the elig ibility criteria following the screening visit, the assigned treatment group and dose level w ill be provided to the site study team through the IRT prior to the first study treatment administration. The participant will be informed of one of the following: •Assigned to a part (Preliminary Safety Cohorts and Part A) and dose cohort in the dose escalation portion of the study. •Assigned to a part (Part B1, B2, C1, or C2) in the combination portion of the study. •Assigned to the expansion portion of the study (Parts D and E) During dose escalation, all participants will be assigned to the Preliminary Safety C ohorts, then Part A until the decision is made to start the co mbination with either nivolumab or ipilimumab. If there are no openings available in the part to which the participant would be assigned by this algorithm, then the par ticipant w ill be assi gned to the next open part/cohort. In the event that multiple cohorts are open in Parts B and/or C simultan eously, participants will be assigned to those cohorts in an alternating fashion. During dose escalation (Preliminary Safety Cohorts a nd Part A), participants who are not evaluable for DLT determination may be replaced (see Section 5.1.2.1 ). Replacement par ticipants w ill be assigned to the same part (Part A) and dose, but will be assigned a new participant number. Please refer to the IRT manual for complete details on replacement of participants.Participants in Parts A, B and C may be repl aced if adequate p aired pretreatment a nd on-treatment biopsy specimens are not obtained. The replacement participant will receive the same treatment as that for the participant being replaced, but a new participant number will be assigned (seeSection 5.1.2.2 and 5.1.2.3 ). 7.2 Blinding This is a non-randomized, open-label study; blinding procedures are not applicable. 7.3 Dosage Modification With the exclusion of the Preliminary Safety Co horts, intra-participant dose escalation or reduction of BMS-986226, nivolumab, or ipilimumab is not permitted in this study in order to allow better evaluation of the safety and efficacy at individual dose levels and schedules. 7.3.1 Treatment Delay Participants who experience a DLT must have the study treatment held.