Furthermore, compensatory upregulation of other immune checkpoints could lead to CD8+ T cell depletion and PD-L1+ T cells suppress neighbouring PD-1+ T cells, resulting in a diminished anti-tumour effect, expansion of Foxp3+ PD-1+ Treg cells after ICI treatment and uptake of IL-2 to suppress effector T-cell function, BRCA2 gene mutations, TAM aggregation, activation of the p38 pathway, and EGFR gene mutations to increase pro-inflammatory cytokines such as IL-6, IL-10, and TGF-β. Here, TGFB1 is linked to neoplasm.