A New Direction in Endometrial Cancer Therapy—PD-1 and PD-L1 Immune Checkpoint Inhibitors—Where Will It Take Us?

Background: Endometrial cancer (EC) remains a significant therapeutic challenge due to its rising incidence and a five-year survival rate of only 16% in cases of metastases or advanced disease when using classical therapy methods. For this reason, more effective methods of treatment are still sought, which currently focus on immunotherapy with the use of PD-1 and PD-L1 inhibitors (ICI), which is the subject of our article. Methods: Articles published in the databases: Pubmed, Web of Science, and ClinicalTrials.gov in the years 2019–2024 were analyzed. Results: ICIs can be used in monotherapy as well as in combination therapy, but it is the latter option that significantly prolongs the median PFS, especially the combination of ICI with PARP inhibitors. Among the available ICIs, pembrolizumab stands out with a large advantage in clinical trials, which is characterized by the lowest mortality resulting from therapy and a small number of grade 3 adverse events. Other inhibitors such as atezolizumab, dostarlimab, durvalumab, nivolumab and avelumab also demonstrate high clinical efficacy, as they prolong median PFS compared to the control group, but more studies are needed in much larger study groups to assess their safety and efficacy in different age groups. Conclusions: Future studies should focus on the efficacy of ICIs in younger groups of patients with EC, as well as on drugs from this group that are used less frequently in clinical trials than pembrolizumab, which would allow for a thorough comparison of the efficacy of drugs with each other and the selection of the drug individually to the patient’s needs.