RecruitingDrug trialINFORM2 Study Uses Nivolumab and Entinostat in Children and Adolescents With High-risk Refractory MalignanciesThe aim of this trial is to determine preliminary activity of the combination treatment with nivolumab and entinostat in children and adolescents with high risk refractory/relapsed/progressive tumors harboring a high mutational load, focal MYC(N) amplification or ATRT-MYC subgroup as well as tumors with high tumor infiltrating lymphocytes (TILs) or a tertiary lymphoid structure (TLS).