PDCD1 and neoplasm: The erythrocytes part could improve siPD‐L1 accumulation in tumors, and the combination of FEGCG/Zn and siPD‐L1 could boost tumor‐killing of T cells likely due to blocking PD‐L1/PD‐1‐mediated inhibitory pathway that dampens the activity of infiltrated CD8+ T cells.