  Detecting planets within protoplanetary disks around young stars is essential
for understanding planet formation and evolution. However, planet detection
using the radial velocity method faces challenges due to strong stellar
activity in these early stages. We aim to detect long-term periodicities in
photometric and spectroscopic time series of the classical T Tauri star (CTTS)
CI Tau, and retrieve evidence for inner embedded planets in its disk. The study
conducted photometric and spectroscopic analyses using K2 and Las Cumbres
Observatory Global Network light curves, and high-resolution spectra from
ESPaDOnS and SPIRou. We focus our radial velocity analysis on a wavelength
domain less affected by spot activity. To account for spot effects, a
quasi-periodic Gaussian process model was applied to K2 light curve, ESPaDOnS,
and SPIRou radial velocity data. Additionally, a detailed bisector analysis on
cross-correlation functions was carried out to understand the cause of
long-term periodicity. We detect coherent periods at $\sim$ 6.6 d, 9 d, $\sim$
11.5 d, $\sim$ 14.2 d and $\sim$ 25.2 d, the latter is seen consistently across
all datasets. Bisector analysis of the cross-correlation functions provides
strong hints for combined activity-induced and Doppler reflex signal in the
radial velocities at a period of 25.2 d. Our analysis suggests that this
periodicity is best explained by the presence of a 3.6$\pm$0.3 M$_{Jup}$,
eccentric (e$\sim$0.58) planet at a semi-major axis of 0.17 au. Our study
outlines the difficulty of searching for disk-embedded planets in the inner 0.1
au's of young and active systems. We demonstrate that, when searching for
planets in actively accreting stars such as CI Tau, the primary limitation is
stellar activity rather than the precision of RV measurements provided by the
instrument.
