RecruitingPhase 2Drug trialStudy of Pembrolizumab, Carboplatin, Paclitaxel, and Radiation for the Treatment of Early-Stage Anal CancerA single arm phase II study of pembrolizumab, carboplatin, paclitaxel, and radiation for the treatment of early-stage anal cancer. There are 2 treatments phases and then surveillance. The first treatment phase is the chemoradiation phase (Cycle 1-6, weekly cycles) which is followed by the maintenance phase (Cycle 7-14, 6 week cycles).