In dose expansion, patients with R/R non-small cell lung cancer will be enrolled in ABBV-514 monotherapy (N=12) and ABBV-514 + BDG (N=12) cohorts, and patients with R/R head and neck squamous cell carcinoma in an ABBV-514 + BDG (N=12) cohort. Enrollment initiated in November 2021, with 30 patients enrolled as of April 2023.