PDCD1 and cancer: This resistance phenotype is attributed to an array of factors, including decreased cancer immunogenicity, inadequate interferon response, alterations in epidermal growth factor receptor (EGFR), exclusion of T-lymphocytes as well as immunosuppression elements within the cancer's microenvironment. Acquired resistance to PD-1/PD-L1 inhibitors entails a scenario wherein these inhibitors initially engender a sustained therapeutic response upon treatment initiation.