The subject of research is the problems of modernization of the subject of labor law and the theory of labor relations in the context of the transformation of the labor sphere The purpose of article is to confirm or disprove hypothesis thatThe methodology of research is formal legal and logical interpretation of Russian Constitution and labor legislation, analysis of the academic publications concerning labor law. Based on the historical analysis of the law structuring process, the direction of development of labor law as a private-public branch of law.The main results, scope of application. It is substantiated that the totality of elements of legal relations, characteristic of both private and public law (freely entering into labor relations on the basis of an agreement, but forced to fulfill obligations under the agreement exclusively by personal labor, obeying the employer’s will in the process of labor activity), should be a system (an interconnected integrative set having an anti-entropic character) in order to function effectively. The removal of some elements from this system entails an imbalance in the system of the labor law branch as a whole, with possible subsequent destruction. On the basis of a systematic approach, the formation and development of the theory of labor relations in domestic legal science are studied. The foundations of the convergent "theory of the plurality of unified labor relations", developed for application in the conditions of transition to new technological paradigms and growing differentiation of forms of labor organization, are proposed and substantiated. This theory was developed on the basis of the “theory of a single indivisible labor relationship” by N.G. Aleksandrov and "the theory of the complex of labor relations" V.N. Skobelkin. On the basis of the theory of plurality of unified labor legal relations, the prospects for expanding the subject of the branch of labor law are determined by including in it emerging new relations that are associated with the use of human labor on a contractual and non-contractual basis. A motivated assumption is formulated that such an expansion of the subject of labor law will make it possible to complete the process begun a century and a half ago and finally remove all contracts providing for the employment of labor from the subject of civil law in favor of labor law. A contract of personal employment between individuals, assuming the equality of the parties to the use of independent labor not with a single employer, will remain civil law. Through the institutions of labor protection, social insurance and social partnership, labor law should begin a systematic expansion to any emerging new form of organization of human labor. After that, a new form of labor organization can be subject to various sets of other industry norms and institutions, the use of which ensures the protection of the employee and an increase in production efficiency. The necessity of changing the presumption of proving the existence of labor relations to proving civil relations is substantiated.Conclusions. The article substantiates the three-subject composition of the participants in the system of legal relations arising from the use of agency labor (contract on the provision of an employee) and the need to establish joint liability of subjects on the side of the employer (solidary employer). It proves the need to release the employee from liability for offenses detected by artificial intelligence. It is proposed to continue research on the prospects for the formation of labor procedural law.