ROCK1 and neoplasm: Using various clinical DR5 agonist antibodies, multiple tumor cell lines, and immune‐sufficient tumor models, here we demonstrate an unexpected PD‐L1 cellular and surface stabilization mechanism which is regulated by DR5 agonist‐activated Rho‐associated kinase‐1 (ROCK1) and proteasome function downstream of death‐inducing signaling complex (DISC).