  We present the radio and X-ray monitoring campaign of the 2019/2020 outburst
of MAXI J1348-630, a new black hole X-ray binary (XRB) discovered in 2019
January. We observed MAXI J1348-630 for $\sim$14 months in the radio band with
MeerKAT and the Australia Telescope Compact Array (ATCA), and in the X-rays
with MAXI and Swift/XRT. Throughout the outburst we detected and tracked the
evolution of the compact and transient jets. Following the main outburst, the
system underwent at least 4 hard-state-only re-flares, during which compact
jets were again detected. For the major outburst, we observed the rise,
quenching, and re-activation of the compact jets, as well as two single-sided
discrete ejecta, launched $\sim$2 months apart and travelling away from the
black hole. These ejecta displayed the highest proper motion ($\gtrsim$100 mas
day$^{-1}$) ever measured for an accreting black hole binary. From the jet
motion, we constrain the ejecta inclination and speed to be $\leq$46$^{\circ}$
and $\geq$0.69 $c$, and the opening angle and transverse expansion speed of the
first component to be $\leq$6$^{\circ}$ and $\leq$0.05 $c$. We also infer that
the first ejection happened at the hard-to-soft state transition, before a
strong radio flare, while the second ejection was launched during a short
excursion from the soft to the intermediate state. After traveling with
constant speed, the first component underwent a strong deceleration, which was
covered with unprecedented detail and suggested that MAXI J1348-630 could be
located inside a low-density cavity in the interstellar medium, as already
proposed for XTE J1550-564 and H1743-322.
