The knockout of ALKBH5 can reduce the infiltration of Tregs in melanoma and enhance the response to anti-PD-1 therapy [99]; MDSCs can induce Tregs production, thus promote tumor angiogenesis and metastasis, so it can also be a target for improving treatment [135]; the polarization of macrophages can affect tumor formation, so altering macrophage polarization in the tumor microenvironment through m6A modification can also provide help in treating cancer [51, 53]; Tumor autophagy leads to tumor immune escape. The gene discussed is PDCD1; the disease is melanoma.