CTLA4 and neoplasm: However, administration of anti-PD-1/PD-L1 agents should be most effective if administered after RT, while CTLA-4 should be administered prior to RT, as PD-L1 levels in tumor and immune cells increase following RT, and anti-CTLA-4 antibodies contribute to the depletion of intratumoral Tregs before RT to mitigate the immune suppression of TME [61].