FIGURE 2.

Biomarkers used in cancer immunology investigations. Various potential biomarkers associated with tumor immunology and immunotherapy have been categorized based on their mechanisms: (1) Genetic markers, including tumor mutation burden, mismatch repair system deficiency, and high microsatellite instability. Next‐generation sequencing technologies can be employed to detect these genetic markers. (2) Surface markers, including PD‐L1, some other inhibitory receptors, and tumor neoantigens. Immunohistochemistry of tumor tissues can be utilized to examine the expression of these surface markers. (3) Cytological markers, including tumor‐infiltrating lymphocytes such as tumor‐infiltrating lymphocytes and exhaustion cells, can be examined by RNA sequencing and immune‐related gene panel scoring. (4) Liquid biopsy markers, including circulating tumor DNA which exists in peripheral blood and can be accessible by blood sampling and analyses. Figure was created with BioRender.com.