This study is being done to find out of NRM-823 is safe and can treat participants with locally advanced or metastatic solid tumors.

Part A of the study will evaluate the safety and tolerability of NRM-823. Part B of the study will further evaluate the safety and tolerability of NRM-823 of the recommended dose identified in PART A in an expansion cohort. Part C will evaluate the addition of a checkpoint inhibitor to NRM-823.

Inclusion Criteria:

• Have histologically- or cytologically-diagnosed NSCLC (squamous or adenocarcinoma), TNBC, HNSCC, ESCC, esophageal adenocarcinoma, gastric/GEJ adenocarcinoma, cervical, endometrial, or ovarian cancer which is advanced or metastatic.
• Have an Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1.
• Adequate liver, renal, pulmonary, and cardiac function.
• Adequate hematologic function.

Exclusion Criteria:

• Has received cytotoxic chemotherapy, biologic anticancer agents, checkpoint inhibitors, or radiation therapy (excluding bone-only radiation therapy) ≤3 weeks or 5 half-lives (whichever is shorter) prior to the first dose of NRM-823
• History of Grade 2 pneumonitis requiring steroids or any Grade 3 or 4 pneumonitis from any prior therapy.
• Has received an investigational therapy <4 weeks or 5 half-lives prior to the first dose of NRM823, whichever is shorter prior to the first dose of NRM-823.
• With the exception of alopecia and Grade ≤2 neuropathy, any unresolved toxicities from prior therapy greater than CTCAE Grade 1 at the time of starting study drug.