PDCD1 and neoplasm: Besides, AlkB homolog 5 (ALKBH5) inhibitor ALK-04 enhances the sensitivity of anti–PD-1 immunotherapy and immune cell recruitment by downregulating MCT4 levels and lactate production in melanoma.492 Moreover, anti-APOC2K70-lac antibody interferes with K70 lactylaton of APOC2, thus thwarting FFA release, blocking the accumulation of Treg cells and sensitizing anti-tumor response of immunotherapy.181