Rudolf Stadler, MD, PhD, University Medical Center Minden, Minden, Germany, gives an update on the Phase II PARCT trial (NCT03357224) investigating the PD-L1 inhibitor atezolizumab for the treatment of stage IIb-IV mycosis fungoides or Sézary syndrome, for patients who become relapsed/refractory (R/R) after a previous systemic treatment. Prof. Stadler discussess challenges around the safety profile of atezolizumab and the need to find biomarkers which enable the identification of patients who would benefit the most from this therapy. This interview took place at the EORTC Cutaneous Lymphoma Group 20-21 meeting in Marseille.