The development of the polymerase chain reaction (PCR) method by Kary Mullis in 1983, for which he received the Nobel Prize in 1993, is one of the most notable achievements in molecular biology. Even with small quantities of biological material, PCR enables the rapid amplification of DNA fragments. PCR has undergone significant refinements and optimisations, transforming it into an indispensable tool across scientific, diagnostic, forensic, and agricultural domains. Recent trends in PCR have focused on enhancing sensitivity, specificity, real-time monitoring, and multiplexing capabilities. The development of Nested PCR, on the other hand, improves specificity by utilising two rounds of amplification, enhancing target detection confidence, and reducing false positives. The capacity of real-time PCR and quantitative PCR (qPCR) to track DNA amplification in real time facilitates precise microbial load estimation and gene expression analysis. Multiplex PCR, which enables the amplification of several DNA fragments at once, by turning RNA into complementary DNA (cDNA), the reverse transcription polymerase chain reaction (RT-PCR) combines a reverse transcription step and enables the amplification of RNA molecules frequently used to assess gene expression. Digital PCR (dPCR) is a highly sensitive third-generation PCR that enables absolute quantification and accurate molecular detection of rare mutations and copy number variation. In the future, PCR technology improvements will produce specialised modifications and cutting-edge methods to meet particular requirements in a variety of fields.