PDCD1 and mismatch repair cancer syndrome 1: An association between MSI-H status and the efficacy of PD-L1/PD-1 inhibitors has been established in a range of solid tumors, including a relatively small number of PC cases; MMR deficiency was sometimes associated with favorable response to anti-PD-1 therapy or PD-L1 expression [29,37,61,167,168,169,170,171,172,173,174].