Challenges and exploration for immunotherapies targeting cold colorectal cancer

Figure 1 Three different types based on immune characteristics. Immune-excluded phenotype: T cells cannot homie from the tumor stroma to the interior of the tumor; Immune-desert phenotype: Anticancer immune initiation error, including insufficient antigen release, insufficient antigen presentation, T cell initiation and activation disorders. TMB: Tumor mutation burden; IFN-γ: Interferon- γ; PD-L1: Programmed cell death 1 Ligand 1.