PDCD1 and neoplasm: As the presence of tumor antigen-specific preexisting T cells that are disabled by tumor PD-L1 expression is likely required for α-PD-1 mAb treatment to work [15], we speculate that Trabectedin treatment may induce tumoral PD-L1 expression by IFN-γ release from effect T cells, namely adaptive resistance mechanism recently described [34], thus providing the target for α-PD-1 mAbs.