An orally available formulation containing a small molecule antagonist of the aryl hydrocarbon receptor (AhR; class E basic helix-loop-helix protein 76; bHLHe76) with potential immunomodulating and antineoplastic activities. Upon oral administration, AhR antagonist BAY2416964 specifically binds to AhR, inhibits AhR activation, and prevents AhR-mediated signaling. Abrogation of AhR activation prevents the activation of immune-tolerant dendritic cells (DCs) and regulatory T-cells (Tregs) in the tumor microenvironment (TME). This may restore the immune response against tumor cells. AhR, a member of the basic helix-loop-helix/Per-Arnt-Sim (bHLH/PAS) family of transcription factors, has important roles in regulating immunity and cellular differentiation. AhR can exhibit both pro-oncogenic and tumor suppressor-like functions depending on the tumor type; therefore, its expression may serve as a negative or positive prognostic factor.