Several challenges exist in the study of TILs. The heterogeneity of tumors and their microenvironments can make it difficult to standardize the assessment of TILs. Moreover, the functional state of these lymphocytes can vary; not all TILs are active or effective against the tumor. Advanced techniques like single-cell RNA sequencing and multiplex immunohistochemistry are being developed to address these issues and provide more detailed insights.
