Among the signaling proteins examined, a notable decrease in phospho‐AKT was observed following anti-mPD-1 treatment, whereas phospho‐Rb, phospho‐MAPK (ERK), and phospho‐S6 levels remained unchanged, indicating that PD‐1 blockade selectively impairs the PI3K/AKT survival pathway, consistent with data obtained using a Lewis lung carcinoma mouse model 21, 22. This evidence concerns the gene RB1 and carcinoma.