The purpose of this first-in-human (FIH) study of BLZ945 given as a single agent or in combination with PDR001 is to characterize the safety, tolerability, pharmacokinetics (PK), pharmacodynamics, and anti-tumor activity of BLZ945, administered orally, as a single agent or in combination with PDR001, administered intravenously (i.v.) in adult patients with advanced solid tumors. Dose escalation will be guided by a Bayesian logistic regression model with overdose control. Once MTD/ RP2D is declared, patients will be enrolled in the phase II part in the selected indications (glioblastoma, pancreatic cancer and triple negative breast cancer) to further assess the preliminary anti-tumor activity of BLZ945 in combination with PDR001. Should signs of anti-tumor activity be seen in the phase I dose escalation with BLZ945 as single agent, a phase II part will be opened in order to further explore BLZ945 single agent efficacy at the recommended dose.