ULK1 and glioblastoma: Based on the existed information that AMPK/ULK1 pathway was closely associated with autophagy [27, 28], and PD-L1 potentially regulated AMPK/ULK1 pathway [31], we next evidenced that PD-L1-ex activated AMPK/ULK1 pathway mediated autophagy in TS-GBM cells (Fig. 5a–f).