Vitamin C is an immunotherapy that augments the efficacy of anti-PD-L1 therapies.

Tumor suppressor TET2 promotes cancer immunity and immunotherapy efficacy

"Conversely, stimulating TET activity by systematic injection of its co-factor, ascorbate/vitamin C, increased chemokine and TILs, leading to enhanced anti-tumor immunity and anti-PD-L1 efficacy and extended lifespan of tumor-bearing mice."

 

Vitamin C has a newly revealed MOA.  It is the rate limiting substance for TET2 activity, and therefore it is a bonafide immunotherapeutic small molecule.