PDCD1 and neoplasm: [72] developed an albumin-phenformin-based NP to block the PD-1/PD-L1 pathway by loading PM (a metformin analog) to induce adenosine 5′-monophosphate-activated protein kinase phosphorylation to reduce PD-L1 expression in tumor cells, achieving PD-1/PD-L1 blockade and solving the problem of tumor recurrence and metastasis after PTT treatment (Fig. 5E) [72].