This is an open-label dose escalation study designed to evaluate the safety and pharmacokinetics of ABBV-085 and determine the recommended Phase 2 dose (as monotherapy or in combination with standard therapies) in subjects with advanced solid tumors.

Inclusion Criteria:

1. Participants with advanced solid tumor that is not amenable to surgical resection or other approved therapeutic options.

2. Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 to 2.

3. Participants must have measurable disease per Response Evaluation Criteria In Solid Tumors (RECIST) version 1.1 or disease evaluable by assessment of tumor antigens:

   - Participants with non-evaluable or non-measurable cancer are eligible if they have a confirmed increase in tumor antigens >=2 x upper limit of normal (ULN).

4. All participants must consent to provide archived diagnostic formalin-fixed paraffin embedded (FFPE) tumor tissue and on study biopsies.

5. Participant has adequate bone marrow, renal, hepatic and cardiac function.

6. Women of childbearing potential must have a negative serum pregnancy test within 14 days prior to initiation of treatment.

Exclusion Criteria:

1. Participant has received anticancer therapy or any investigational therapy within a period of 21 days prior to the first dose of ABBV-085.
2. Uncontrolled metastases to the central nervous system (CNS). Participants with brain metastases are eligible provided they have shown clinical and radiographic stable disease for at least 4 weeks after definitive therapy and have not used steroids for at least 4 weeks prior to first dose of ABBV-085.
3. Unresolved adverse events >= Grade 2 from prior anticancer therapy, except for alopecia.
4. Participant has ongoing hemolysis.
5. Major surgery within <=28 days prior to the first dose of ABBV-085.
6. Clinically significant uncontrolled condition(s).
7. Participant has history of major immunologic reaction to any auristatin-based and /or Immunoglobulin G (IgG) containing agent.