A Study of Relatlimab Plus Nivolumab in Combination With Chemotherapy vs. Nivolumab in Combination With Chemotherapy as First Line Treatment for Participants With Stage IV or Recurrent Non-small Cell Lung Cancer (NSCLC)

TRAEs Leading to Discontinuation in Part 1

Number of participants with treatment related adverse events (TRAEs) leading to discontinuation based on grade. AE is defined as any new untoward medical occurrence or worsenig of a preexising medical condition in a clinical investigation participant administered study treatment and that does not necessarily have a causal relationship with this treatment. Grading will be determined for severity according to the NCI CTCAE v5.0

Time frame: From first dose to 30 days post last dose of study therapy (Approximately 32.8 Months)

Number of Participants With a Treatment Related AEs in Part 1

Number of participants with a treatment related AE in part 1. AE is defined as any new untoward medical occurrence or worsenig of a preexising medical condition in a clinical investigation participant administered study treatment and that does not necessarily have a causal relationship with this treatment. Grading will be determined for severity according to the NCI CTCAE v5.0

Time frame: From first dose to 30 days post last dose of study therapy (Approximately 32.8 Months)

Number of Participants With Treatment Releted SAEs in Part 1

A serious adverse event (SAE) is defined as any untoward medical occurrence that at any dose, results in death, is life-threatening, requires inpatient hospitalization or causes prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, or is an important medical event (defined as a medical event(s) that may not be immediately life-threatening or result in death or hospitalization but, based upon appropriate medical and scientific judgment, may jeopardize the participant or may require intervention \[e.g., medical, surgical\] to prevent one of the other serious outcomes listed in the definition). Grading will be determined for severity according to the NCI CTCAE v5.0.

Time frame: From first dose to 30 days post last dose of study therapy (Approximately 32.8 Months)

Number of Participants With Treatment Releted Select AEs in Part 1

AE is defined as any new untoward medical occurrence or worsenig of a preexising medical condition in a clinical investigation participant administered study treatment and that does not necessarily have a causal relationship with this treatment. Select Adverse Events (AEs) will be determined for severity according to the NCI CTCAE v5.0.

Time frame: From first dose to 30 days post last dose of study therapy (Approximately 32.8 Months)

ORR by PD-L1 Expression Per RECISTS v1.1 by BICR in Part 2

Objective Response Rate (ORR) per RECIST v1.1 by BICR is defined as the number of participants in the randomized population who achieve a best overall response (BOR) of confirmed complete response (CR) or confirmed partial response (PR) based on BICR assessments (using RECIST v1.1) divided by the number of participants in the population. BOR is defined as the best response, as determined by the BICR, recorded between the date of randomization and the date of first objectively documented progression per RECIST v1.1 or the date of subsequent therapy, whichever occurs first.

Time frame: Approximately 14.8 Months

DoR Per RECISTS v1.1 by BICR in Part 2

Duration of Response (DOR) will be assessed by BICR. It is defined as the time between the date of first documented response (CR or PR) that is subsequently confirmed, to the date of the first objectively documented tumor progression as determined by the BICR (per RECIST v1.1), or death due to any cause, whichever occurs first.

Time frame: Approximately up to 13.7 months

Number of Participants With a AE in Part 2

Number of participants with an adverse event (AE). AE is defined as any new untoward medical occurrence or worsenig of a preexising medical condition in a clinical investigation participant administered study treatment and that does not necessarily have a causal relationship with this treatment. Grading will be determined for severity according to the NCI CTCAE v5.0.

Time frame: From first dose to 30 days post last dose of study therapy (Approximately 14.8 Months)

Number of Participants With a Treatment Related AEs in Part 2

AE is defined as any new untoward medical occurrence or worsenig of a preexising medical condition in a clinical investigation participant administered study treatment and that does not necessarily have a causal relationship with this treatment. Grading will be determined for severity according to the NCI CTCAE v5.0.

Time frame: From first dose to 30 days post last dose of study therapy (Approximately 14.8 Months)

Number of Participants With a Treatment Related SAEs in Part 2

SAE is defined as a life-threatening (defined as an event in which the participant was at risk of death at the time of the event; it does not refer to an event which hypothetically might have caused death if it were more severe). SAEs can also result in death. The AE requires inpatient hospitalization or causes prolongation of existing hospitalization. Results in persistent or significant disability/incapacity. Is a congenital anomaly/birth defect. Is an important medical event (defined as a medical event(s) that may not be immediately lifethreatening or result in death or hospitalization but, based upon appropriate medical and scientific judgment, may jeopardize the participant or may require intervention \[e.g., medical, surgical\] to prevent one of the other serious outcomes listed in the definition above.) Grading will be determined for severity according to the NCI CTCAE v5.0.

Time frame: From first dose to 30 days post last dose of study therapy (Approximately 14.8 Months)

Number of Participants With Endocrine Immune-mediated Adverse Events in Part 2

IMAEs are AEs consistent with an immune-mediated mechanism or immune-mediated component for which non-inflammatory etiologies (eg, infection or tumor progression) have been ruled out. IMAEs can include events with an alternate etiology which were exacerbated by the induction of autoimmunity. Grading will be determined for severity according to the NCI CTCAE v5.0.

Time frame: From first dose to 30 days post last dose of study therapy (Approximately 14.8 Months)

ORR by LAG-3 Expression Per RECISTS v1.1 by BICR in Part 2

Objective Response Rate (ORR) per RECIST v1.1 by BICR is defined as the number of participants in the randomized population who achieve a best overall response (BOR) of confirmed complete response (CR) or confirmed partial response (PR) based on BICR assessments (using RECIST v1.1) divided by the number of participants in the population. BOR is defined as the best response, as determined by the BICR, recorded between the date of randomization and the date of first objectively documented progression per RECIST v1.1 or the date of subsequent therapy, whichever occurs first.

Time frame: On Going

ORR by FG-L1 Expression Per RECISTS v1.1 by BICR in Part 2

Objective Response Rate (ORR) per RECIST v1.1 by BICR is defined as the number of participants in the randomized population who achieve a best overall response (BOR) of confirmed complete response (CR) or confirmed partial response (PR) based on BICR assessments (using RECIST v1.1) divided by the number of participants in the population. BOR is defined as the best response, as determined by the BICR, recorded between the date of randomization and the date of first objectively documented progression per RECIST v1.1 or the date of subsequent therapy, whichever occurs first.

Time frame: Ongoing

PFS Per RECISTS v1.1 by BICR in Part 2

Progression Free Survival is defined as the time between the date of randomization and the first date of documented progression, based on BICR assessments (per RECIST v1.1), or death due to any cause, whichever occurs first.

Time frame: Ongoing

PFS by PD-L1 Expression Per RECISTS v1.1 by BICR in Part 2

Progression Free Survival is defined as the time between the date of randomization and the first date of documented progression, based on BICR assessments (per RECIST v1.1), or death due to any cause, whichever occurs first.

Time frame: Ongoing

PFS by LAG-3 Expression Per RECISTS v1.1 by BICR in Part 2

Progression Free Survival is defined as the time between the date of randomization and the first date of documented progression, based on BICR assessments (per RECIST v1.1), or death due to any cause, whichever occurs first.

Time frame: Ongoing

PFS by FG-L1 Expression Per RECISTS v1.1 by BICR in Part 2

Progression Free Survival is defined as the time between the date of randomization and the first date of documented progression, based on BICR assessments (per RECIST v1.1), or death due to any cause, whichever occurs first.

Time frame: Ongoing

Number of Participants With Treatment Releted Select AEs in Part 2

AE is defined as any new untoward medical occurrence or worsenig of a preexising medical condition in a clinical investigation participant administered study treatment and that does not necessarily have a causal relationship with this treatment. Select Adverse Events (AEs) will be determined for severity according to the NCI CTCAE v5.0.

Time frame: Ongoing