Track Finding in CMS for the Level-1 Trigger at the HL-LHC

The High Luminosity LHC (HL-LHC) will deliver luminosities of up to $5\times 10^{34}$ Hz/cm$^2$, with an average of about 140 overlapping proton-proton collisions per bunch crossing. These extreme pileup conditions place stringent requirements on the trigger system to be able to cope with the resulting event rates. A key component of the CMS upgrade for HL-LHC is a track trigger system which would identify tracks with transverse momentum above 2 GeV/c already at the first-level trigger. This paper presents the status of proposals for implementing the L1 tracking in conjunction with the planned upgrade for the silicon tracker of the CMS experiment.