Inclusion Criteria:  Age ≥18 years (Cohort 2e only: Age ≥12 years and weighing>40 kg).  Phase 1:  Histologically or cytologically confirmed metastatic solid tumor with documented ROS1 rearrangement. Cohorts 2a, 2b, 2c and 2d: Histologically or cytologically confirmed metastatic NSCLC with ROS1 rearrangement. Cohort 2e: Histologically or cytologically confirmed metastatic solid tumor (other than NSCLC) with ROS1 rearrangement. Prior anticancer treatment (except cohort 2a). Phase 1: Must have evaluable disease (target or nontarget) according to RECIST 1.1. Phase 2: Must have measurable disease according to RECIST 1.1. Adequate baseline organ function and bone marrow reserve.  Exclusion Criteria:  Patient's cancer has a known primary driver alteration other than ROS1. Known allergy/hypersensitivity to excipients of NVL-520. Major surgery within 4 weeks of study entry. Ongoing or recent anticancer therapy. Actively receiving systemic treatment or direct medical intervention on another therapeutic clinical study.