This study involves taking a study drug called venetoclax with or without standard of care chemotherapy. The overall goal of this study is to see if adding venetoclax to standard chemotherapy leads to improved survival for children and young adults with relapsed acute myeloid leukemia (AML). The study may last up to 9 years and will enroll male and female patients from the ages of 29 days to 21 years of age.

The goal of this observational study is to describe the safety and effectiveness of larotrectinib in patients with locally advanced or metastatic TRK fusion cancer for whom a decision to treat with larotrectinib has been made before enrollment. This study will enroll participants with any tumors harboring the NTRK gene fusion including Soft Tissue Sarcomas, Central Nervous System, Melanoma, and Thyroid cancers.