All participants who discontinue study treatment should comply with protocol specified follow-up procedures as outlined in Section 5.1.3 . The only exception to this requirement is when a participant withdraws consent for all study proce dures, including posttreatment study follow-up, or loses the ability to consent freely (eg, imprisonment, involuntarily incarceration for the treatment of either a psychiatric or a physical illness). If study treatment is discontinued prior to the participant’s completion of the study, the reason for the discontinuation must be documented in th e participant’s medical records and entered on the appropriate CRF page. 8.1.1 Criteria to Resume Treatment Subsequent dosing with the study treatment may resume once drug-related DLT AEs resolve to Grade 1 or baseline. Revised Protocol No.: 04 Date: 31-May-2019 94 Approved 5.0 v Approved 1.0 v Clinical Protocol CA021002 BMS-986226 anti-ICOS In agreement with the Sponsor, after evaluation of the risk/benefit ratio, participants with selected drug-related AE th at meet DLT criteria may resume tr eatment once the AE is resolved to Grade ≤1 or baseline value (see Section 7.3.5 ). Participants who experience AEs and do not meet the criteria for permanent discontinuation as outlined in Section 8.1 may resume study treatment under the following criteria: •Participants may resume treatment with study tr eatment when the drug-related AE(s) resolve to Grade ≤1 or baseline value, with the following exceptions: −Participants may resume treatment in the presence of Grade 2 fatigue. −Participants who have not experienced a Grade 3 drug-related skin AE may resume treatment in the presence of Grade 2 skin toxicity. −Participants with Grade 2 uveitis, episcleritis, iritis, eye pain, or blurred vision not meeting DLT criteria ( Section 7.3.2 ) must resolve to baseline prior to resuming study treatment. •For participants with Grade 2 AST, ALT, or total bilirubin elevations, dosing may resume when laboratory values return to baseline and management with corticosteroids (if needed) is complete. −Participants with combined Grade 2 AS T/ALT and total bilirubin values meeting DLT criteria (Section 7.3.2) should have treatment permanently discontinued. •Drug-related pulmonary toxicity, diarrhea, or colitis must have resolved to baseline before treatment is resumed. Participants with persistent Grade 1 pneumonitis after completion of a steroid taper over at least 1 month may be eligible for retreatment if discussed with, and approved by, the BMS Medical Monitor/Study Director (or designee). •Participants with drug-related endocrinopathies adequately controlled with only physiologic hormone replacement may resume treatment. If the criteria to resume tr eatment are met, the participant s hould restar t treatment at the next nominally scheduled time point per protocol. Even if the criteria to resume treatment are met, the consideration to re-initiate study tr eatment under the following excepti on will be made on a case-by-case ba sis after considering the overall benefit/risk profile, and in consultation between the investigator and the Sponsor. Any AE with clinical risk will be asse ssed on a case-by-case basis with the investigator and the BMS Medical Monitor/Study Dir ector (or designee) to determine the risks and benefits of continuing on the treatment following resolution versus discontinuing therapy permanently. If study treatment is delayed > 6 weeks, the par ticipant must be permanently discontinued from study treatment, except as specified in Section 7.3.5. 8.1.2 Treatment Beyond Disease Progression As described in Sectio n 5.4.3 , accumulating evidence indicates that a minority of participants with solid tumors treated with immunotherapy may derive clinical benefit despite init ial evidence of progressive disease. Participants will be permitted to continue on study treatment beyond initial Revised Protocol No.: 04 Date: 31-May-2019 95 Approved 5.0 v Approved 1.0 v Clinical Protocol CA021002 BMS-986226 anti-ICOS RECIST v1.1 defined progressive disease (see Appendix 5 ) or PCWG3 (prostate cancer only) (see Appendix 11) as long as they meet the following criteria: •Investigator-assessed clinical benefit and no rapid disease progression •Continue to meet all other study protocol eligibility criteria •Tolerance of study treatment •Stable performance status •Treatment beyond progression will not d elay an imminent intervention to prevent serious complications of disease progression (eg, CNS metastases) •Participant provides written informed consent prior to receiving any additional BMS-986226, nivolumab, or ipilimumab treatment using an ICF describing any reasonably foreseeable risks or discomforts, or other alternative treatment options The assessment of clinical benefit s hould take into acc ount whether the participant is clinically deteriorating and unlikely to receive further benefit from continued treatment. If the investigator feels that the participant continues to achieve clinical benefit by continuing tr eatment with the study treatment, the participant should re main on the study and continue to r eceive monitoring according to the Schedule of Activities (see Section 2 ). All decisions to continue treatment beyond initial progression must be discussed with the BMS Medical Monitor/Study Director (or designee),and an assessment of the risk/benefit of continuing with study treatment must be documented in the study records. Participants will be re-consented to explain the rationale for this ongoing treatment. 8.1.3 Discontinuation Due to Further Progression (Confirmed Progression) Participants will continue to receive monitoring according to the on-tr eatment assessments in Section 2. Radiographic assessment by CT (preferred) or MRI (described in Section 9.1 )i s required when participants continue post-progression study tr eatment and should be performed at each scheduled tumor assessment 4 to 6 weeks following initial disease progression to determine whether there has been continued progressive dis ease or not. Participants should discontinue study treatment upon evidence of further progression, defined as an additional 10% or gr eater increase in tumor burden volume from the time of initial progress ion (including all target lesions and new measurable lesions). The tumor burden volume from the time of initial progression should be used as the reference baseline for comparison with the post-progression assessment. Any new lesion considered non -measurable at th e time of initial progression may become measurable and therefore must be included in the tumor burden measurement as follows: •For solid tumors: new lesions are considered measurable at the time of initial progression if the longest diameter is at least 10 mm (except for pathological lymph nodes, which must have a short axis of at least 15 mm). Revised Protocol No.: 04 Date: 31-May-2019 96 Approved 5.0 v Approved 1.0 v Clinical Protocol CA021002 BMS-986226 anti-ICOS For statist ical analyses that include the investigator-assessed progression date, participants who continue treatment be yond initial investigator-assessed, RECIST v1.1 or PCWG3 (prostate cancer only) defined progression will be considered to have investigator-assessed progressive disease at the time of the initial progression event. For participants who discontinue post-progressi on study treatment, no additional radiographic assessments will be required.