RecruitingPhase 2Drug trialA Phase II Study of the Combination of Pembrolizumab and ATRA Combination Treatment of Relapsed HL and B-NHLThis is a Phase II single-center open label trial of the combination of ATRA and pembrolizumab treatment in patients with histologically proven, relapsed or refractory Hodgkin Lymphoma or B-Non-Hodgkin-lymphoma.