Additional Study Information: DB-1311 (study drug) is an investigational antibody-drug conjugate (antibody that guides the study drug to cancer cells) composed of an anti-B7-H3 (a protein associated with worse overall survival and drug resistance) antibody and P1021 (slows DNA replication in cancer cells). "Investigational" means the study drug being tested is not approved by the United States (U.S.) Food and Drug Administration (FDA). The main goal of this study is to test whether the study drug is safe and tolerable in patients with certain types of cancer. This study will also measure the amount of the study drug in patients' blood at different time points, determine whether antibodies (proteins in the blood) against the study drug are produced in the body, and assess the effect of the study drug on the disease. In addition, this study may also explore the relationship between biomarkers (a biological molecule found in blood or tissue that may be a sign of a disease) in the body and the effect of the study drug on the disease. This is the first time DB-1311 is being tested in humans.