Adaptive 5G architecture consisting of three functional sections (four antenna components, tunable matching network (TMN), and radio frequency (RF) front-end package) is proposed, analyzed, and verified. In the 5G millimeter-wave (mmWave) spectrum, the RF performance is highly dependent on the specific antenna package technology. However, compact antenna packages, oftentimes, result in undesired interference between the antenna elements. This eventually leads to severe RF performance degradation. For the first time in the literature, an mmWave 5G RFIC and the TMN are integrated for efficient operation that is applicable to real-life 5G mobile devices. Moreover, the proposed antenna-in-package (AiP) architecture enables independent frequency control at multiple frequencies. The proposed solution is simulated and measured at the system level. As a result, the devised AiP solution exhibits a simulated effective isotropic radiated power (EIRP) of 22.05-23.96 dBm at the cumulative distribution function (CDF) of 50% by applying the conducted power of 17 dBm (per channel), and the peak gain of the antenna exhibits 13.7 dBi at 27 GHz (state A) and 12.6 dBi at 28 GHz (state B) with an amplifier having an output power of 5 dBm.