Inclusion Criteria: - All participants must have a histologically or cytologically confirmed, advanced, unresectable/metastatic, solid malignancy measurable by RECIST v1.1, and have received, be refractory to, ineligible for, intolerant of, or refused existing therapy(ies) known to provide clinical benefit for the condition of the participant. - Participant must be ≥ 18 years or the legal age of consent in the jurisdiction in which the study is taking place, inclusive, at the time of signing the ICF. - Participants in Part 1A may have NSCLC, SCCHN, MSS-CRC, gastric/GEJ adenocarcinoma, urothelial carcinoma, PDAC, melanoma or breast cancer (TNBC and ER+HER2-). - Participants in Part 1B1 and 2B1 must have NSCLC and, if known, should have documented status for EGFR, KRAS, ALK, ROS1, RET, NTRK, MET exon 14 skipping mutations, and BRAF V600E.Participants must have received platinum-based chemotherapy and anti-PD-(L)1 therapy, if eligible and available. - Participants in Parts 1B2, 2B2, and 1C must have cutaneous, acral, mucosal, or unknown primary melanoma. Participants with uveal/ocular melanoma are excluded. Participants must be melanoma 2L+. - Participants in Part 1B3 must have advanced or metastatic MSS-CRC. - Participants in Part 2A may have advanced solid tumors (advanced, unresectable, or metastatic NSCLC, advanced, unresectable, hormone resistant ER+HER2-breast cancer or pancreatic adenocarcinoma [PDAC]) based on emerging data. - Participants in Part 2B3 must have advanced or metastatic MSS-CRC. - For all participants in Part 1C cohort, a tumor sample from a ("fresh") biopsy [core biopsy (at least 4 passages recommended), punch biopsy, excisional biopsy or surgical specimen] must be obtained (obtained within 1 month of the start of the Screening, if there are tumor sites that can be biopsied with acceptable clinical risk). Exclusion Criteria: - History of life threatening immune mediated toxicity related to prior T-cell agonist or checkpoint inhibitor therapy, except those that are unlikely to re-occur with standard countermeasures. - 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 Inclusion/Exclusion criteria apply.