A Study of BMS-986449 With and Without Nivolumab in Participants With Advanced Solid Tumors

Inclusion Criteria:

* All participants must have a histologically or cytologically confirmed, advanced, unresectable/metastatic, solid malignancy (measurable by Response Evaluation Criteria in Solid Tumors [RECIST] v1.1), and have received, be refractory to, ineligible for, or intolerant of existing therapy(ies) known to provide clinical benefit for the condition of the participant.

1. Part 1A may have a solid malignancy of any histology.
2. Part 1B is restricted to participants with Non-small cell lung cancer (NSCLC).
3. Part 1C is restricted to participants with Triple-negative breast cancer (TNBC).
4. Tumor biopsy must be obtained for all participants (unless medically precluded).

Exclusion Criteria:

1. History of Grade ≥ 3 toxicity related to prior T-cell agonist or checkpoint inhibitor therapy (eg, anti-cytotoxic T-lymphocyte-associated antigen 4 [CTLA-4], or anti-PD- 1/programmed death-ligand 1 [PD-L1] treatment, or any other antibody or drug specifically targeting T-cell co-stimulation or other immune checkpoint pathways) except those that are unlikely to re-occur with standard countermeasures.
2. Current or recent (within 3 months of study intervention administration) gastrointestinal disease or gastrointestinal surgery (eg, intestinal/gastric/colon resection) that could impact the absorption of study intervention.
3. Any significant acute or chronic medical illness which would interfere with study intervention or follow-up in the opinion of the investigator.

Other protocol-defined criteria may apply.