Predictive testing is a crucial part of the complete diagnostic process of non-small cell lung cancer (NSCLC) and a necessary requirement in order to determine proper course of treatment. However, the possibilities of testing and the spectrum of examined markers are quickly evolving as a result of the progress in diagnostic and therapeutic possibilities, and as such it is necessary to regularly update the current guidelines to achieve proper standards of care in routine practice.To provide a complex overview of the current problematics of predictive testing in NSCLC at a molecular level, considering also the evaluation of PD-L1 expression based on the international and national guidelines. To summarize the current state of predictive testing employed in NSCLC in the Czech Republic.Predictive testing in NSCLC is a part of routine diagnostic practice; however, as a result of the expanding spectrum of diagnostic and therapeutic possibilities, it is undergoing significant development. The existing method of the sequential testing of individual markers is becoming unsuitable; given the increasing number of potential predictors and complex molecular testing, the use of new generation sequencing appears to represent a more suitable solution. The immunohistochemical evaluation of PD-L1 expression is also a necessary part of predictive testing in NSCLC.