PDCD1 and permanent neonatal diabetes mellitus-pancreatic and cerebellar agenesis syndrome: However, results from earlier clinical trials on immunotherapies for blocking PD1/PD-L1 in PACA patients did not yield encouraging results, with the obtained poor responses attributed to immunosuppressive conditions in the PACA tumor microenvironment (TME), including a scarcity of CD8+ T cells and a recruitment of myeloid cells, respectively (4).