Although IDH1 mutations that encode tumor-specific epitopes can be immunologically exploited, the tumor microenvironment, including regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), and tumor-associated macrophages (TAMs) (Almand et al., 2001; Dieckmann et al., 2001; Chen and Mellman, 2013; Zhou et al., 2015), may suppress antitumor immunity and play a critical role in cancer development and progression. Here, IDH1 is linked to cancer.