The present study explores the potential of the new sulfonamide derivatives coupled with salicylamide or anisamide scaffold as immune checkpoint PD-L1 inhibitors. Based on in silico virtual screening 32 derivatives were synthesized and tested in vitro as PD-L1 inhibitors using screening ELISA assay. Five compounds gave promising results with more than 50% inhibition. The most active, with activity 57.152%, was 5-Chloro-N-(4-(N-(3-fluorophenyl)sulfamoyl)phenethyl)salicylamide (30). The other compounds were 5-Chloro-2-methoxy-N-(4-(N-(4-fluorophenyl)sulfamoyl)benzyl)benzamide (4, 53.327%), 5-Chloro-2-methoxy-N-(4-(N-(4-methylphenyl)sulfamoyl)phenethyl)benzamide (17, 51.253%), 5-Chloro-N-(4-(N-(4-(trifluoromethyl) phenyl)sulfamoyl)phenethyl)salicylamide (31, 51.058%) and 5-Chloro-2-methoxy-N-(4-(N-(2,4-difluorophenyl)sulfamoyl) benzyl)benzamide (7, 50.993). The synthesized compounds were tested for potential anti-proliferative activity against some cell lines to evaluate the safety of PD-L1 active compounds and compare their anti-proliferative activity with that of other compounds under investigation. All compounds were found to be safe and did not have any cytotoxic effects on the fibroblast cell lines. Moreover, compounds 4, 7, 17, and 30 showed little to no anti-proliferative activity against the cell lines used in this study except compound 4, which displayed anti-proliferative activity against PC-3 (66.640%). On the other hand, compound 31 showed remarkable activities against the cell lines MCF-7, DU-145, and PC-3. Human prostate cancer cell line PC-3 is highly sensitive to some of the 32 compounds tested at 10 μM. The molecular docking study and ADMET analysis of the bioactive compounds were used to elucidate the mode-of-action mechanism.